如何从 spring 引导 jpa 查询中获取特定属性
how to get specific properties from spring boot jpa query
我使用 spring boot jpa 和 h2 数据库创建了简单的 rest api。默认查询像 findAll 一样工作。但我想在存储库中执行本机查询。但是当我尝试它时,我得到了错误并且我一直在执行本机查询。
型号class
@Entity
public class employe {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long emId;
private String firstname;
private String lastname;
private String address;
private String bithday;
public Long getEmId() {
return emId;
}
public void setEmId(Long emId) {
this.emId = emId;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getLastname() {
return lastname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getBithday() {
return bithday;
}
public void setBithday(String bithday) {
this.bithday = bithday;
}
}
存储库
@Repository
public interface employeRepository extends JpaRepository<employe,Long> {
/* @Query("SELECT s FROM employe s WHERE s.firstname =?jenny")
Optional<employe> findemplayByName(String name);*/
@Query(nativeQuery = true, value="SELECT firstname FROM employe")
List<employe> limit();
}
控制器class
@RestController
@RequestMapping("/employe")
public class employeController {
@Autowired
private employeRepository repository;
public employeController(employeRepository repository) {
this.repository = repository;
}
@PostMapping("/insert")
public employe saveEmploye(@RequestBody employe model){
return repository.save(model);
}
@GetMapping("/view")
public List<employe> viewEmployee(){
return repository.findAll();
}
@GetMapping("/view/limit")
public List<employe> viewEmployeelimit(){
return repository.limit();
}
}
application.properties
spring.h2.console.enabled=true
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
错误
:: Spring Boot :: (v2.6.6)
2022-04-19 19:52:59.798 INFO 9136 --- [ main] com.example.blezor.BlezorApplication : Starting BlezorApplication using Java 17.0.2 on DESKTOP-B1OP7V0 with PID 9136 (C:\Users\ayesh\IdeaProjects\Springboot_blezor\target\classes started by ayesh in C:\Users\ayesh\IdeaProjects\Springboot_blezor)
2022-04-19 19:52:59.798 INFO 9136 --- [ main] com.example.blezor.BlezorApplication : No active profile set, falling back to 1 default profile: "default"
2022-04-19 19:53:01.242 INFO 9136 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2022-04-19 19:53:01.404 INFO 9136 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 128 ms. Found 1 JPA repository interfaces.
2022-04-19 19:53:02.560 INFO 9136 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2022-04-19 19:53:02.592 INFO 9136 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2022-04-19 19:53:02.592 INFO 9136 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.60]
2022-04-19 19:53:02.888 INFO 9136 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2022-04-19 19:53:02.888 INFO 9136 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2973 ms
2022-04-19 19:53:03.013 INFO 9136 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2022-04-19 19:53:03.342 INFO 9136 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2022-04-19 19:53:03.373 INFO 9136 --- [ main] o.s.b.a.h2.H2ConsoleAutoConfiguration : H2 console available at '/h2-console'. Database available at 'jdbc:h2:mem:testdb'
2022-04-19 19:53:03.732 INFO 9136 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [name: default]
2022-04-19 19:53:03.826 INFO 9136 --- [ main] org.hibernate.Version : HHH000412: Hibernate ORM core version 5.6.7.Final
2022-04-19 19:53:04.185 INFO 9136 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2022-04-19 19:53:04.420 INFO 9136 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2022-04-19 19:53:05.654 INFO 9136 --- [ main] o.h.e.t.j.p.i.JtaPlatformInitiator : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2022-04-19 19:53:05.669 INFO 9136 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2022-04-19 19:53:06.309 WARN 9136 --- [ main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2022-04-19 19:53:06.985 INFO 9136 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2022-04-19 19:53:07.008 INFO 9136 --- [ main] com.example.blezor.BlezorApplication : Started BlezorApplication in 8.165 seconds (JVM running for 9.28)
2022-04-19 19:53:08.274 INFO 9136 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2022-04-19 19:53:08.274 INFO 9136 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2022-04-19 19:53:08.281 INFO 9136 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 6 ms
2022-04-19 19:53:17.538 WARN 9136 --- [nio-8080-exec-4] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 42122, SQLState: 42S22
2022-04-19 19:53:17.538 ERROR 9136 --- [nio-8080-exec-4] o.h.engine.jdbc.spi.SqlExceptionHelper : Column "em_id" not found [42122-200]
2022-04-19 19:53:17.564 ERROR 9136 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute query; SQL [SELECT firstname FROM employe]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute query] with root cause
org.h2.jdbc.JdbcSQLSyntaxErrorException: Column "em_id" not found [42122-200]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:453) ~[h2-1.4.200.jar:1.4.200]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:429) ~[h2-1.4.200.jar:1.4.200]
at org.h2.message.DbException.get(DbException.java:205) ~[h2-1.4.200.jar:1.4.200]
at org.h2.message.DbException.get(DbException.java:181) ~[h2-1.4.200.jar:1.4.200]
at org.h2.jdbc.JdbcResultSet.getColumnIndex(JdbcResultSet.java:3195) ~[h2-1.4.200.jar:1.4.200]
at org.h2.jdbc.JdbcResultSet.get(JdbcResultSet.java:3268) ~[h2-1.4.200.jar:1.4.200]
at org.h2.jdbc.JdbcResultSet.getLong(JdbcResultSet.java:680) ~[h2-1.4.200.jar:1.4.200]
at com.zaxxer.hikari.pool.HikariProxyResultSet.getLong(HikariProxyResultSet.java) ~[HikariCP-4.0.3.jar:na]
at org.hibernate.type.descriptor.sql.BigIntTypeDescriptor.doExtract(BigIntTypeDescriptor.java:63) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:47) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:257) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:253) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:243) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.hydrate(AbstractStandardBasicType.java:329) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.extractKeysFromResultSet(Loader.java:811) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:735) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.getRowsFromResultSet(Loader.java:1047) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.processResultSet(Loader.java:998) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doQuery(Loader.java:967) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:357) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2868) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2850) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2682) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.list(Loader.java:2677) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:2186) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.internal.AbstractSharedSessionContract.list(AbstractSharedSessionContract.java:1204) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.query.internal.NativeQueryImpl.doList(NativeQueryImpl.java:177) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1617) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.query.Query.getResultList(Query.java:165) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:128) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:90) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:155) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:143) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:137) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:121) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:159) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:138) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.transaction.interceptor.TransactionInterceptor.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:145) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.18.jar:5.3.18]
at jdk.proxy2/jdk.proxy2.$Proxy94.limit(Unknown Source) ~[na:na]
at com.example.blezor.employeController.viewEmployeelimit(employeController.java:38) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.18.jar:5.3.18]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.60.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.18.jar:5.3.18]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.60.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.18.jar:5.3.18]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.18.jar:5.3.18]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.18.jar:5.3.18]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:889) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
h2 数据库
public interface EmployeeFirstnameProjection {
public String getFirstname();
}
@Repository
public interface employeRepository extends JpaRepository<employe,Long> {
@Query("SELECT emp.firstname FROM employe emp")
List<EmployeeFirstnameProjection> limit(); // Check the return type.
}
我们这里做的是基于界面的投影。有关详细信息,请查看 jpa repository projections
我使用 spring boot jpa 和 h2 数据库创建了简单的 rest api。默认查询像 findAll 一样工作。但我想在存储库中执行本机查询。但是当我尝试它时,我得到了错误并且我一直在执行本机查询。
型号class
@Entity
public class employe {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long emId;
private String firstname;
private String lastname;
private String address;
private String bithday;
public Long getEmId() {
return emId;
}
public void setEmId(Long emId) {
this.emId = emId;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getLastname() {
return lastname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getBithday() {
return bithday;
}
public void setBithday(String bithday) {
this.bithday = bithday;
}
}
存储库
@Repository
public interface employeRepository extends JpaRepository<employe,Long> {
/* @Query("SELECT s FROM employe s WHERE s.firstname =?jenny")
Optional<employe> findemplayByName(String name);*/
@Query(nativeQuery = true, value="SELECT firstname FROM employe")
List<employe> limit();
}
控制器class
@RestController
@RequestMapping("/employe")
public class employeController {
@Autowired
private employeRepository repository;
public employeController(employeRepository repository) {
this.repository = repository;
}
@PostMapping("/insert")
public employe saveEmploye(@RequestBody employe model){
return repository.save(model);
}
@GetMapping("/view")
public List<employe> viewEmployee(){
return repository.findAll();
}
@GetMapping("/view/limit")
public List<employe> viewEmployeelimit(){
return repository.limit();
}
}
application.properties
spring.h2.console.enabled=true
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
错误
:: Spring Boot :: (v2.6.6)
2022-04-19 19:52:59.798 INFO 9136 --- [ main] com.example.blezor.BlezorApplication : Starting BlezorApplication using Java 17.0.2 on DESKTOP-B1OP7V0 with PID 9136 (C:\Users\ayesh\IdeaProjects\Springboot_blezor\target\classes started by ayesh in C:\Users\ayesh\IdeaProjects\Springboot_blezor)
2022-04-19 19:52:59.798 INFO 9136 --- [ main] com.example.blezor.BlezorApplication : No active profile set, falling back to 1 default profile: "default"
2022-04-19 19:53:01.242 INFO 9136 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2022-04-19 19:53:01.404 INFO 9136 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 128 ms. Found 1 JPA repository interfaces.
2022-04-19 19:53:02.560 INFO 9136 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2022-04-19 19:53:02.592 INFO 9136 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2022-04-19 19:53:02.592 INFO 9136 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.60]
2022-04-19 19:53:02.888 INFO 9136 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2022-04-19 19:53:02.888 INFO 9136 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2973 ms
2022-04-19 19:53:03.013 INFO 9136 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2022-04-19 19:53:03.342 INFO 9136 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2022-04-19 19:53:03.373 INFO 9136 --- [ main] o.s.b.a.h2.H2ConsoleAutoConfiguration : H2 console available at '/h2-console'. Database available at 'jdbc:h2:mem:testdb'
2022-04-19 19:53:03.732 INFO 9136 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [name: default]
2022-04-19 19:53:03.826 INFO 9136 --- [ main] org.hibernate.Version : HHH000412: Hibernate ORM core version 5.6.7.Final
2022-04-19 19:53:04.185 INFO 9136 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2022-04-19 19:53:04.420 INFO 9136 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2022-04-19 19:53:05.654 INFO 9136 --- [ main] o.h.e.t.j.p.i.JtaPlatformInitiator : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2022-04-19 19:53:05.669 INFO 9136 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2022-04-19 19:53:06.309 WARN 9136 --- [ main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2022-04-19 19:53:06.985 INFO 9136 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2022-04-19 19:53:07.008 INFO 9136 --- [ main] com.example.blezor.BlezorApplication : Started BlezorApplication in 8.165 seconds (JVM running for 9.28)
2022-04-19 19:53:08.274 INFO 9136 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2022-04-19 19:53:08.274 INFO 9136 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2022-04-19 19:53:08.281 INFO 9136 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 6 ms
2022-04-19 19:53:17.538 WARN 9136 --- [nio-8080-exec-4] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 42122, SQLState: 42S22
2022-04-19 19:53:17.538 ERROR 9136 --- [nio-8080-exec-4] o.h.engine.jdbc.spi.SqlExceptionHelper : Column "em_id" not found [42122-200]
2022-04-19 19:53:17.564 ERROR 9136 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute query; SQL [SELECT firstname FROM employe]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute query] with root cause
org.h2.jdbc.JdbcSQLSyntaxErrorException: Column "em_id" not found [42122-200]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:453) ~[h2-1.4.200.jar:1.4.200]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:429) ~[h2-1.4.200.jar:1.4.200]
at org.h2.message.DbException.get(DbException.java:205) ~[h2-1.4.200.jar:1.4.200]
at org.h2.message.DbException.get(DbException.java:181) ~[h2-1.4.200.jar:1.4.200]
at org.h2.jdbc.JdbcResultSet.getColumnIndex(JdbcResultSet.java:3195) ~[h2-1.4.200.jar:1.4.200]
at org.h2.jdbc.JdbcResultSet.get(JdbcResultSet.java:3268) ~[h2-1.4.200.jar:1.4.200]
at org.h2.jdbc.JdbcResultSet.getLong(JdbcResultSet.java:680) ~[h2-1.4.200.jar:1.4.200]
at com.zaxxer.hikari.pool.HikariProxyResultSet.getLong(HikariProxyResultSet.java) ~[HikariCP-4.0.3.jar:na]
at org.hibernate.type.descriptor.sql.BigIntTypeDescriptor.doExtract(BigIntTypeDescriptor.java:63) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:47) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:257) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:253) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:243) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.type.AbstractStandardBasicType.hydrate(AbstractStandardBasicType.java:329) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.extractKeysFromResultSet(Loader.java:811) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:735) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.getRowsFromResultSet(Loader.java:1047) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.processResultSet(Loader.java:998) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doQuery(Loader.java:967) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:357) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2868) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2850) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2682) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.Loader.list(Loader.java:2677) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:2186) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.internal.AbstractSharedSessionContract.list(AbstractSharedSessionContract.java:1204) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.query.internal.NativeQueryImpl.doList(NativeQueryImpl.java:177) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1617) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.hibernate.query.Query.getResultList(Query.java:165) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final]
at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:128) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:90) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:155) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:143) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:137) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:121) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:159) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:138) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.6.3.jar:2.6.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.transaction.interceptor.TransactionInterceptor.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137) ~[spring-tx-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:145) ~[spring-data-jpa-2.6.3.jar:2.6.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.18.jar:5.3.18]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.18.jar:5.3.18]
at jdk.proxy2/jdk.proxy2.$Proxy94.limit(Unknown Source) ~[na:na]
at com.example.blezor.employeController.viewEmployeelimit(employeController.java:38) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.18.jar:5.3.18]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.18.jar:5.3.18]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.60.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.18.jar:5.3.18]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.60.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.18.jar:5.3.18]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.18.jar:5.3.18]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.18.jar:5.3.18]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.18.jar:5.3.18]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:889) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.60.jar:9.0.60]
at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
h2 数据库
public interface EmployeeFirstnameProjection {
public String getFirstname();
}
@Repository
public interface employeRepository extends JpaRepository<employe,Long> {
@Query("SELECT emp.firstname FROM employe emp")
List<EmployeeFirstnameProjection> limit(); // Check the return type.
}
我们这里做的是基于界面的投影。有关详细信息,请查看 jpa repository projections