@Autowired 依赖项具有空成员
@Autowired dependency has null members
我的配置class:
@Configuration
public class TimeOutConfig {
@Value("${value1}")
private int value1;
@Value("${value2}")
private int value2;
@Bean()
User boTimeOut() {
System.out.println("In BOTimeOutConfig");
BeanTest b1 = new BeanTest(value1, value2);
User u1 = new User(b1);
return u1;
}
@Value("${value3}")
private int value3;
@Value("${value4}")
private int value4;
@Bean(name = "BSETimeout")
User getBSEUser() {
System.out.println("In BSETimeOutConfig");
User u2 = new User( new BeanTest(value3, value4));
return u2;
}
}
BeanTest Class:
@Component
public class BeanTest {
private int v1;
private int v2;
BeanWebClient b1;
public BeanTest(){}
public BeanTest(int v1, int v2){
this.v1=v1;
this.v2=v2;
beanWebClient();
}
public BeanWebClient beanWebClient() {
//System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+v1+v2);
b1 = new BeanWebClient(v1,v2);
System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+b1.getV1()+" "+b1.getV2());
return b1;
}
public void message()
{
b1.webClientMessage();
//System.out.println("V1= "+v1+" V2= "+v2);
}
}
BeanWebClientClass:
@Component
public class BeanWebClient {
private int v1;
private int v2;
public BeanWebClient(int v1, int v2){
this.v1=v1;
this.v2=v2;
System.out.println("Received from BeanTest "+v1+" "+v2);
}
public BeanWebClient(){
}
public int getV1() {
return v1;
}
public int getV2() {
return v2;
}
public void webClientMessage(){
System.out.println("In BeanWebClient class, printing from autowired dependency "+v1+" "+v2);
}
}
我的用户class:
@Component
public class User {
@Autowired
private BeanTest beanTest;
public User(BeanTest beanTest){
this.beanTest=beanTest;
}
public void message()
{
beanTest.message();
}
public User() {
//System.out.println("user create... hashCode :" + this.hashCode());
}
}
最后，我的服务class：
@Service
public class BeanService {
@Autowired
@Qualifier("boTimeOut")
private User boUser;
@Autowired
@Qualifier("BSETimeout")
private User bseUser;
public void printBO()
{
boUser.message();
}
public void printBSE()
{
bseUser.message();
}
}
我试图了解组件和自动装配依赖项在 spring 引导中是如何工作的。在我的用户 class 中，自动装配的 BeanTest class 在配置期间被初始化——所有必要的打印语句都被执行。但是当我调用服务的函数 class 时，自动装配的用户依赖项对于 beanTest 及其成员为 null。与此相反，当我只是在我的用户 class 中创建 BeanTest 对象时，一切都按预期工作。这就是我的意思：
@Component
public class User {
BeanTest beanTest;
public User(BeanTest beanTest){
this.beanTest=beanTest;
}
public void message()
{
beanTest.message();
}
public User() {
//System.out.println("user create... hashCode :" + this.hashCode());
}
}
我有点理解用户 class 中自动装配的 bean 从容器中获取是空的。由于我在我的服务 class 中自动装配特定的用户依赖项，我不明白为什么它不起作用。
有人可以解释一下我是否以及如何将 BeanTest class 正确地自动连接到用户 class 中。
抱歉有这么多代码文件。
产出
这是我在没有 @Autowire
的情况下手动创建 BeanTest 对象时得到的输出
In BOTimeOutConfig
Received from BeanTest 10 20
In BeanTest class beanWebClient() method execution v1 and v2: 10 20
In BSETimeOutConfig
Received from BeanTest 30 40
In BeanTest class beanWebClient() method execution v1 and v2: 30 40
2021-11-13 14:37:58.161 WARN 404383 --- [ main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2021-11-13 14:37:58.613 INFO 404383 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-11-13 14:37:58.622 INFO 404383 --- [ main] c.paytmmoney.errordb.ErrordbApplication : Started ErrordbApplication in 4.04 seconds (JVM running for 4.379)
2021-11-13 14:38:07.768 INFO 404383 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-11-13 14:38:07.768 INFO 404383 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2021-11-13 14:38:07.769 INFO 404383 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 1 ms
In /test method
In BeanWebClient class, printing from autowired dependency 10 20
In /test method
In BeanWebClient class, printing from autowired dependency 30 40
当我自动装配 BeanTest Class 这是输出：
In BOTimeOutConfig
Received from BeanTest 10 20
In BeanTest class beanWebClient() method execution v1 and v2: 10 20
In BSETimeOutConfig
Received from BeanTest 30 40
In BeanTest class beanWebClient() method execution v1 and v2: 30 40
2021-11-13 14:40:36.072 WARN 404724 --- [ main] JpaBaseConfiguration$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
2021-11-13 14:40:36.585 INFO 404724 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-11-13 14:40:36.596 INFO 404724 --- [ main] c.paytmmoney.errordb.ErrordbApplication : Started ErrordbApplication in 4.353 seconds (JVM running for 4.75)
2021-11-13 14:40:45.081 INFO 404724 --- [nio-8080-exec-2] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-11-13 14:40:45.081 INFO 404724 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2021-11-13 14:40:45.082 INFO 404724 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet : Completed initialization in 1 ms
In /test method
2021-11-13 14:40:45.204 ERROR 404724 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
at com.paytmmoney.errordb.repository.BeanTest.message(BeanTest.java:42) ~[main/:na]
at com.paytmmoney.errordb.repository.User.message(User.java:22) ~[main/:na]
at com.paytmmoney.errordb.service.BeanService.printBO(BeanService.java:21) ~[main/:na]
我正在使用休息控制器调用服务中的函数 class。
谢谢！！！
鉴于您正在 TimeOutConfig 中自行创建 BeanTest 和 User 实例，请删除 [=] 中的所有 @Component 和 @Autowired 注释13=]、BeanWebClient 和 User 如下：
public class BeanTest {
private int v1;
private int v2;
BeanWebClient b1;
public BeanTest(){}
public BeanTest(int v1, int v2){
this.v1=v1;
this.v2=v2;
beanWebClient();
}
public BeanWebClient beanWebClient() {
//System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+v1+v2);
b1 = new BeanWebClient(v1,v2);
System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+b1.getV1()+" "+b1.getV2());
return b1;
}
public void message() {
b1.webClientMessage();
//System.out.println("V1= "+v1+" V2= "+v2);
}
}
public class BeanWebClient {
private int v1;
private int v2;
public BeanWebClient(int v1, int v2) {}
this.v1=v1;
this.v2=v2;
System.out.println("Received from BeanTest "+v1+" "+v2);
}
public BeanWebClient(){ }
public int getV1() {
return v1;
}
public int getV2() {
return v2;
}
public void webClientMessage(){
System.out.println("In BeanWebClient class, printing from autowired dependency "+v1+" "+v2);
}
}
public class User {
private BeanTest beanTest;
public User(BeanTest beanTest) {
this.beanTest=beanTest;
}
public User() {
//System.out.println("user create... hashCode :" + this.hashCode());
}
public void message() {
beanTest.message();
}
}
我的配置class:
@Configuration
public class TimeOutConfig {
@Value("${value1}")
private int value1;
@Value("${value2}")
private int value2;
@Bean()
User boTimeOut() {
System.out.println("In BOTimeOutConfig");
BeanTest b1 = new BeanTest(value1, value2);
User u1 = new User(b1);
return u1;
}
@Value("${value3}")
private int value3;
@Value("${value4}")
private int value4;
@Bean(name = "BSETimeout")
User getBSEUser() {
System.out.println("In BSETimeOutConfig");
User u2 = new User( new BeanTest(value3, value4));
return u2;
}
}
BeanTest Class:
@Component
public class BeanTest {
private int v1;
private int v2;
BeanWebClient b1;
public BeanTest(){}
public BeanTest(int v1, int v2){
this.v1=v1;
this.v2=v2;
beanWebClient();
}
public BeanWebClient beanWebClient() {
//System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+v1+v2);
b1 = new BeanWebClient(v1,v2);
System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+b1.getV1()+" "+b1.getV2());
return b1;
}
public void message()
{
b1.webClientMessage();
//System.out.println("V1= "+v1+" V2= "+v2);
}
}
BeanWebClientClass:
@Component
public class BeanWebClient {
private int v1;
private int v2;
public BeanWebClient(int v1, int v2){
this.v1=v1;
this.v2=v2;
System.out.println("Received from BeanTest "+v1+" "+v2);
}
public BeanWebClient(){
}
public int getV1() {
return v1;
}
public int getV2() {
return v2;
}
public void webClientMessage(){
System.out.println("In BeanWebClient class, printing from autowired dependency "+v1+" "+v2);
}
}
我的用户class:
@Component
public class User {
@Autowired
private BeanTest beanTest;
public User(BeanTest beanTest){
this.beanTest=beanTest;
}
public void message()
{
beanTest.message();
}
public User() {
//System.out.println("user create... hashCode :" + this.hashCode());
}
}
最后，我的服务class：
@Service
public class BeanService {
@Autowired
@Qualifier("boTimeOut")
private User boUser;
@Autowired
@Qualifier("BSETimeout")
private User bseUser;
public void printBO()
{
boUser.message();
}
public void printBSE()
{
bseUser.message();
}
}
我试图了解组件和自动装配依赖项在 spring 引导中是如何工作的。在我的用户 class 中，自动装配的 BeanTest class 在配置期间被初始化——所有必要的打印语句都被执行。但是当我调用服务的函数 class 时，自动装配的用户依赖项对于 beanTest 及其成员为 null。与此相反，当我只是在我的用户 class 中创建 BeanTest 对象时，一切都按预期工作。这就是我的意思：
@Component
public class User {
BeanTest beanTest;
public User(BeanTest beanTest){
this.beanTest=beanTest;
}
public void message()
{
beanTest.message();
}
public User() {
//System.out.println("user create... hashCode :" + this.hashCode());
}
}
我有点理解用户 class 中自动装配的 bean 从容器中获取是空的。由于我在我的服务 class 中自动装配特定的用户依赖项，我不明白为什么它不起作用。 有人可以解释一下我是否以及如何将 BeanTest class 正确地自动连接到用户 class 中。 抱歉有这么多代码文件。
产出 这是我在没有 @Autowire
的情况下手动创建 BeanTest 对象时得到的输出In BOTimeOutConfig
Received from BeanTest 10 20
In BeanTest class beanWebClient() method execution v1 and v2: 10 20
In BSETimeOutConfig
Received from BeanTest 30 40
In BeanTest class beanWebClient() method execution v1 and v2: 30 40
2021-11-13 14:37:58.161 WARN 404383 --- [ main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2021-11-13 14:37:58.613 INFO 404383 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-11-13 14:37:58.622 INFO 404383 --- [ main] c.paytmmoney.errordb.ErrordbApplication : Started ErrordbApplication in 4.04 seconds (JVM running for 4.379)
2021-11-13 14:38:07.768 INFO 404383 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-11-13 14:38:07.768 INFO 404383 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2021-11-13 14:38:07.769 INFO 404383 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 1 ms
In /test method
In BeanWebClient class, printing from autowired dependency 10 20
In /test method
In BeanWebClient class, printing from autowired dependency 30 40
当我自动装配 BeanTest Class 这是输出：
In BOTimeOutConfig
Received from BeanTest 10 20
In BeanTest class beanWebClient() method execution v1 and v2: 10 20
In BSETimeOutConfig
Received from BeanTest 30 40
In BeanTest class beanWebClient() method execution v1 and v2: 30 40
2021-11-13 14:40:36.072 WARN 404724 --- [ main] JpaBaseConfiguration$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
2021-11-13 14:40:36.585 INFO 404724 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-11-13 14:40:36.596 INFO 404724 --- [ main] c.paytmmoney.errordb.ErrordbApplication : Started ErrordbApplication in 4.353 seconds (JVM running for 4.75)
2021-11-13 14:40:45.081 INFO 404724 --- [nio-8080-exec-2] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-11-13 14:40:45.081 INFO 404724 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2021-11-13 14:40:45.082 INFO 404724 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet : Completed initialization in 1 ms
In /test method
2021-11-13 14:40:45.204 ERROR 404724 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
at com.paytmmoney.errordb.repository.BeanTest.message(BeanTest.java:42) ~[main/:na]
at com.paytmmoney.errordb.repository.User.message(User.java:22) ~[main/:na]
at com.paytmmoney.errordb.service.BeanService.printBO(BeanService.java:21) ~[main/:na]
我正在使用休息控制器调用服务中的函数 class。
谢谢！！！
鉴于您正在 TimeOutConfig 中自行创建 BeanTest 和 User 实例，请删除 [=] 中的所有 @Component 和 @Autowired 注释13=]、BeanWebClient 和 User 如下：
public class BeanTest {
private int v1;
private int v2;
BeanWebClient b1;
public BeanTest(){}
public BeanTest(int v1, int v2){
this.v1=v1;
this.v2=v2;
beanWebClient();
}
public BeanWebClient beanWebClient() {
//System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+v1+v2);
b1 = new BeanWebClient(v1,v2);
System.out.println("In BeanTest class beanWebClient() method execution v1 and v2: "+b1.getV1()+" "+b1.getV2());
return b1;
}
public void message() {
b1.webClientMessage();
//System.out.println("V1= "+v1+" V2= "+v2);
}
}
public class BeanWebClient {
private int v1;
private int v2;
public BeanWebClient(int v1, int v2) {}
this.v1=v1;
this.v2=v2;
System.out.println("Received from BeanTest "+v1+" "+v2);
}
public BeanWebClient(){ }
public int getV1() {
return v1;
}
public int getV2() {
return v2;
}
public void webClientMessage(){
System.out.println("In BeanWebClient class, printing from autowired dependency "+v1+" "+v2);
}
}
public class User {
private BeanTest beanTest;
public User(BeanTest beanTest) {
this.beanTest=beanTest;
}
public User() {
//System.out.println("user create... hashCode :" + this.hashCode());
}
public void message() {
beanTest.message();
}
}