使用注释或Java配置通过构造函数注入请求范围bean而不使用xml配置

时间：2016-10-08 19:34:33

标签： spring dependency-injection spring-boot spring-rest

我使用以下控制器，服务和bean代码创建了一个示例Spring启动休息应用程序。

@RestController
public class SampleController {

    @Autowired
    SampleService sampleService;

    @Autowired
    User user;

    @ResponseBody
    @GetMapping(value="/user/add")
    public String addUser(User user) {
        return sampleService.getUserName();
    }
}

@Component
public class SampleService {


    private User user;

    public User getUser() {
        return user;
    }

    @Required
    public void setUser(User user) {
        this.user = user;
    }

    public String getUserName() {
        return "user name is "+this.getUser();
    }
}

@RequestScope
@Component
public class User {

    private String username;

    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

@Configuration
public class RequestBean {

    @Bean
    @Scope(scopeName = "request", proxyMode = ScopedProxyMode.TARGET_CLASS)
    public User initUser() {
        User user = new User();
        return user;
    }
}

当我启动春季启动应用程序时，我收到以下错误

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sampleController': Unsatisfied dependency expressed through field 'sampleService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sampleService' defined in file [<path>\samplespringrest\target\classes\com\example\SampleService.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanInitializationException: Property 'user' is required for bean 'sampleService'
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:569) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:349) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1219) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:751) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861) ~[spring-context-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at com.example.SamplespringrestApplication.main(SamplespringrestApplication.java:10) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_65]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_65]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_65]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_65]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.4.1.RELEASE.jar:1.4.1.RELEASE]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sampleService' defined in file [<path>/SampleService.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanInitializationException: Property 'user' is required for bean 'sampleService'
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:207) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1128) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1056) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:566) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    ... 24 common frames omitted
Caused by: org.springframework.beans.factory.BeanInitializationException: Property 'user' is required for bean 'sampleService'
    at org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor.postProcessPropertyValues(RequiredAnnotationBeanPostProcessor.java:156) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1219) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) ~[spring-beans-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    ... 33 common frames omitted

请帮我解决这个问题。

提前致谢。

更新

在我更新我的服务类之后

@Component
public class SampleService {

    @Autowired
    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public String getUserName() {
        return "user name is "+this.getUser().getUsername();
    }
}

我收到的回复是“用户名为空”

1 个答案:

答案 0 :(得分：0)

实际上，您已根据请求范围限制了User bean的生命周期，同时在SampleService中使用 @Required 作为其setter。所以你在申请开始时没有得到任何要求 - ＆gt;用户bean没有创建 - ＆gt;必需的注释抛出异常。从@RequestScope注释文档中可以清楚地看到：

  

{@ code @RequestScope}是{@link Scope @Scope}的专业版   一个*生命周期绑定到当前Web请求的组件。

所以你的配置激起了这个例外。

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