无法在 ApplicationContext.xml 中声明 Bean
Cannot Declare Beans inside ApplicationContext.xml
答对者有奖
我的实现如下：
NextShipmentDaoImpl.java
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
LoginController.java
@Controller
public class LoginController {
@Autowired
private NextShipmentDao nextShipmentDao;
public void setNextShipmentDao(NextShipmentDao nextShipmentDao) {
this.nextShipmentDao = nextShipmentDao;
}
在像这样创建所需的上述 bean 时：
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl">
<property name="dataSource" ref="dataSource"></property>
</bean>
ApplicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/board" />
<property name="username" value="root" />
<property name="password" value="root" />
</bean>
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl">
<property name="dataSource" ref="dataSource"></property>
</bean>
<security:http auto-config="true" >
<security:intercept-url pattern="/index*" access="ROLE_USER" />
<security:form-login login-page="/login.htm" default-target-url="/index.htm"
authentication-failure-url="/loginerror.htm" />
<security:logout logout-success-url="/logout.htm" />
</security:http>
<context:component-scan base-package="com.ibrahim.controller,com.ibrahim.domain,com.ibrahim.dao" />
<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/views/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
一切正常。但是当我尝试创建一个 bean 时，这会显示错误
SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loginController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ibrahim.dao.NextShipmentDao com.ibrahim.controller.LoginController.nextShipmentDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nextShipmentDao' defined in ServletContext resource [/WEB-INF/board-dao.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:288)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1116)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4728)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5166)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1399)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ibrahim.dao.NextShipmentDao com.ibrahim.controller.LoginController.nextShipmentDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nextShipmentDao' defined in ServletContext resource [/WEB-INF/board-dao.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:514)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:285)
... 22 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nextShipmentDao' defined in ServletContext resource [/WEB-INF/board-dao.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1007)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:953)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:487)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:912)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:855)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:486)
... 24 more
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:163)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1000)
... 35 more
Caused by: java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.jdbc.support.JdbcAccessor.afterPropertiesSet(JdbcAccessor.java:134)
at org.springframework.jdbc.core.JdbcTemplate.<init>(JdbcTemplate.java:165)
at com.ibrahim.dao.NextShipmentDaoImpl.<init>(NextShipmentDaoImpl.java:28)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
... 37 more
May 07, 2015 12:21:48 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Error listenerStart
May 07, 2015 12:21:48 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/13.1SecuringUrlAcces] startup failed due to previous errors
May 07, 2015 12:21:48 PM org.apache.catalina.core.ApplicationContext log
INFO: Closing Spring root WebApplicationContext
May 07, 2015 12:21:48 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
May 07, 2015 12:21:48 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-nio-8009"]
May 07, 2015 12:21:48 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 12402 ms
这是我的 NextShipmentDaoImpl.java
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
JdbcTemplate jdbcTemplate= new JdbcTemplate(dataSource);
@Override
public List<NextShipment> display() {
String sql = "SELECT * FROM NEXTSHIPMENT";
List<NextShipment> shipments = new ArrayList<NextShipment>();
List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);
for (Map row : rows) {
NextShipment shipment = new NextShipment();
shipment.setOid((String) row.get("OID"));
shipment.setAddress((String) row.get("ADDRESS"));
shipment.setPack_Date((Date) row.get("PACK_DATE"));
shipment.setIsAvailable((Boolean) row.get("ISAVAILABLE"));
shipment.setAssignShipper((String) row.get("ASSIGNSHIPPER"));
shipment.setInTransit((Boolean) row.get("InTransit"));
shipments.add(shipment);
}
return shipments;
}
}
基于XML的配置时代已经结束。
我强烈推荐你使用Annotated Configuration
像这样：
@Configuration
@EnableWebMvc
@EnableTransactionManagement
@ComponentScan(basePackages = "com.myapp.*")
public class AppConfiguration extends WebMvcConfigurerAdapter {
@Bean
public DataSource myDataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("<full.driver.class.name>");
dataSource.setUrl("url");
dataSource.setUsername("dit");
dataSource.setPassword("pass");
return dataSource;
}
[...] other Beans like TransactionManager....
}
堆栈跟踪显示：
- 您在
loginController 中正确地自动装配了 nextShipmentDAO
- 但是
dataSource 属性 是 null 是 NextShipmentDAOImpl bean
- 异常发生在
JdbcTemplate初始化
NextShipmentDAOImpl 给出了原因：您正确地注入了数据源，但在构建时初始化了 JdbcTemplate。所以这就是发生的事情：
- jvm 创建一个 NextShipmentDaoImpl 对象
- jvm初始化对象的所有字段包括jdbcTemplate
- spring 设置数据源字段...太迟了！
[@M.Deinum在评论中提到了，但我没有给予足够的重视]
您永远不会在创建时使用注入字段，因为那时它还没有被注入。在设置所有属性后，您应该使用 spring 调用的初始化方法：
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
JdbcTemplate jdbcTemplate;
void init(void) {
jdbcTemplate = new JdbcTemplate(dataSource);
}
并以这种方式声明 bean :
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl"
init-method="init">
<property name="dataSource" ref="dataSource"></property>
</bean>
NextShipmentDaoImpl.java 看起来像这样
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
JdbcTemplate jdbcTemplate;
public NextShipmentDaoImpl(DataSource dataSource) {
this.dataSource = dataSource;
}
在上面的代码行中，我在其实现函数本身中声明了 JdbcTemplate。用在什么地方。
我声明的相关 bean 是：
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl">
<constructor-arg ref="dataSource"></constructor-arg>
</bean>
登录控制器保持不变：
@Controller
public class LoginController {
@Autowired
private NextShipmentDao nextShipmentDao;
public void setNextShipmentDao(NextShipmentDao nextShipmentDao) {
this.nextShipmentDao = nextShipmentDao;
}
我已将 spring 和 spring 安全罐从 3.2.4 转移到 3.2.7
问题就这样解决了。
答对者有奖 我的实现如下：
NextShipmentDaoImpl.java
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
LoginController.java
@Controller
public class LoginController {
@Autowired
private NextShipmentDao nextShipmentDao;
public void setNextShipmentDao(NextShipmentDao nextShipmentDao) {
this.nextShipmentDao = nextShipmentDao;
}
在像这样创建所需的上述 bean 时：
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl">
<property name="dataSource" ref="dataSource"></property>
</bean>
ApplicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/board" />
<property name="username" value="root" />
<property name="password" value="root" />
</bean>
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl">
<property name="dataSource" ref="dataSource"></property>
</bean>
<security:http auto-config="true" >
<security:intercept-url pattern="/index*" access="ROLE_USER" />
<security:form-login login-page="/login.htm" default-target-url="/index.htm"
authentication-failure-url="/loginerror.htm" />
<security:logout logout-success-url="/logout.htm" />
</security:http>
<context:component-scan base-package="com.ibrahim.controller,com.ibrahim.domain,com.ibrahim.dao" />
<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/views/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
一切正常。但是当我尝试创建一个 bean 时，这会显示错误
SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loginController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ibrahim.dao.NextShipmentDao com.ibrahim.controller.LoginController.nextShipmentDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nextShipmentDao' defined in ServletContext resource [/WEB-INF/board-dao.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:288)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1116)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4728)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5166)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1399)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ibrahim.dao.NextShipmentDao com.ibrahim.controller.LoginController.nextShipmentDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nextShipmentDao' defined in ServletContext resource [/WEB-INF/board-dao.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:514)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:285)
... 22 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nextShipmentDao' defined in ServletContext resource [/WEB-INF/board-dao.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1007)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:953)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:487)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:912)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:855)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:486)
... 24 more
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ibrahim.dao.NextShipmentDaoImpl]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:163)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1000)
... 35 more
Caused by: java.lang.IllegalArgumentException: Property 'dataSource' is required
at org.springframework.jdbc.support.JdbcAccessor.afterPropertiesSet(JdbcAccessor.java:134)
at org.springframework.jdbc.core.JdbcTemplate.<init>(JdbcTemplate.java:165)
at com.ibrahim.dao.NextShipmentDaoImpl.<init>(NextShipmentDaoImpl.java:28)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
... 37 more
May 07, 2015 12:21:48 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Error listenerStart
May 07, 2015 12:21:48 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/13.1SecuringUrlAcces] startup failed due to previous errors
May 07, 2015 12:21:48 PM org.apache.catalina.core.ApplicationContext log
INFO: Closing Spring root WebApplicationContext
May 07, 2015 12:21:48 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
May 07, 2015 12:21:48 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-nio-8009"]
May 07, 2015 12:21:48 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 12402 ms
这是我的 NextShipmentDaoImpl.java
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
JdbcTemplate jdbcTemplate= new JdbcTemplate(dataSource);
@Override
public List<NextShipment> display() {
String sql = "SELECT * FROM NEXTSHIPMENT";
List<NextShipment> shipments = new ArrayList<NextShipment>();
List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);
for (Map row : rows) {
NextShipment shipment = new NextShipment();
shipment.setOid((String) row.get("OID"));
shipment.setAddress((String) row.get("ADDRESS"));
shipment.setPack_Date((Date) row.get("PACK_DATE"));
shipment.setIsAvailable((Boolean) row.get("ISAVAILABLE"));
shipment.setAssignShipper((String) row.get("ASSIGNSHIPPER"));
shipment.setInTransit((Boolean) row.get("InTransit"));
shipments.add(shipment);
}
return shipments;
}
}
基于XML的配置时代已经结束。
我强烈推荐你使用Annotated Configuration
像这样：
@Configuration
@EnableWebMvc
@EnableTransactionManagement
@ComponentScan(basePackages = "com.myapp.*")
public class AppConfiguration extends WebMvcConfigurerAdapter {
@Bean
public DataSource myDataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("<full.driver.class.name>");
dataSource.setUrl("url");
dataSource.setUsername("dit");
dataSource.setPassword("pass");
return dataSource;
}
[...] other Beans like TransactionManager....
}
堆栈跟踪显示：
- 您在
loginController 中正确地自动装配了 - 但是
dataSource属性 是 null 是NextShipmentDAOImplbean - 异常发生在
JdbcTemplate初始化
nextShipmentDAO
NextShipmentDAOImpl 给出了原因：您正确地注入了数据源，但在构建时初始化了 JdbcTemplate。所以这就是发生的事情：
- jvm 创建一个 NextShipmentDaoImpl 对象
- jvm初始化对象的所有字段包括jdbcTemplate
- spring 设置数据源字段...太迟了！
[@M.Deinum在评论中提到了，但我没有给予足够的重视]
您永远不会在创建时使用注入字段，因为那时它还没有被注入。在设置所有属性后，您应该使用 spring 调用的初始化方法：
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
JdbcTemplate jdbcTemplate;
void init(void) {
jdbcTemplate = new JdbcTemplate(dataSource);
}
并以这种方式声明 bean :
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl"
init-method="init">
<property name="dataSource" ref="dataSource"></property>
</bean>
NextShipmentDaoImpl.java 看起来像这样
public class NextShipmentDaoImpl implements NextShipmentDao{
private DataSource dataSource;
JdbcTemplate jdbcTemplate;
public NextShipmentDaoImpl(DataSource dataSource) {
this.dataSource = dataSource;
}
在上面的代码行中，我在其实现函数本身中声明了 JdbcTemplate。用在什么地方。
我声明的相关 bean 是：
<bean id="nextShipmentDao" class="com.ibrahim.dao.NextShipmentDaoImpl">
<constructor-arg ref="dataSource"></constructor-arg>
</bean>
登录控制器保持不变：
@Controller
public class LoginController {
@Autowired
private NextShipmentDao nextShipmentDao;
public void setNextShipmentDao(NextShipmentDao nextShipmentDao) {
this.nextShipmentDao = nextShipmentDao;
}
我已将 spring 和 spring 安全罐从 3.2.4 转移到 3.2.7 问题就这样解决了。