java：spring使用【XXXPostProcessor】添加bean定义，修改bean定义、代理bean

news2024/11/25 4:48:10

# 项目代码资源：

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https://download.csdn.net/download/chenhz2284/89433361

# 项目代码

【pom.xml】

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.3.12.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
    <version>2.3.12.RELEASE</version>
</dependency>
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.2.11</version>
</dependency>

【application.properties】

server.port=8080
spring.application.name=myBeanMain

management.server.port=7001
management.endpoints.web.exposure.include=*

【IMainBean4.java】

package com.chz.myBeanMain.bean;

public interface IMainBean4
{
    String getName();
}

【MainBean1.java】

package com.chz.myBeanMain.bean;

@Slf4j
@Getter
@Setter
@Component
public class MainBean1 {

    public MainBean1()
    {
        log.info("chz >>> MainBean1.<init>()");
    }

    private String name = "MainBean1";
}

【MainBean2.java】

package com.chz.myBeanMain.bean;

@Slf4j
@Getter
@Setter
// @Component   // 注意没有注解
public class MainBean2 {

    public MainBean2()
    {
        log.info("chz >>> MainBean2.<init>()");
    }

    private String name = "MainBean2";
}

【MainBean3.java】

package com.chz.myBeanMain.bean;

@Slf4j
@Getter
@Setter
// @Component   // 注意没有注解
public class MainBean3 {

    public MainBean3()
    {
        log.info("chz >>> MainBean3.<init>()");
    }

    private String name = "MainBean3";
}

【MainBean4.java】

package com.chz.myBeanMain.bean;

@Slf4j
@Getter
@Setter
@Component
public class MainBean4 implements IMainBean4 {

    public MainBean4()
    {
        log.info("chz >>> MainBean4.<init>()");
    }

    private String name = "MainBean4";
}

【MainBean4Proxy.java】

package com.chz.myBeanMain.bean;

public class MainBean4Proxy implements IMainBean4{

    private MainBean4 mainBean4;

    public MainBean4Proxy(MainBean4 mainBean4)
    {
        this.mainBean4 = mainBean4;
    }

    @Override
    public String getName() {
        return "[我被代理了："+ mainBean4.getName()+"]";
    }
}

【MainController.java】

package com.chz.myBeanMain.controller;

@Slf4j
@RestController
@RequestMapping("/main")
public class MainController {

    @Autowired(required = false)
    private MainBean1 mainBean1;

    @Autowired(required = false)
    private MainBean2 mainBean2;

    @Autowired(required = false)
    private MainBean3 mainBean3;

    @Autowired(required = false)
    private IMainBean4 mainBean4;

    @GetMapping("/mainBean1")
    public String mainBean1() {
        return "mainBean1: " + mainBean1.getName();
    }

    @GetMapping("/mainBean2")
    public String mainBean2() {
        return "mainBean2: " + mainBean2.getName();
    }

    @GetMapping("/mainBean3")
    public String mainBean3() {
        return "mainBean3: " + mainBean3.getName();
    }

    @GetMapping("/mainBean4")
    public String mainBean4() {
        return "mainBean4: " + mainBean4.getName();
    }
}

【MyBeanDefinitionRegistryPostProcessor.java】

package com.chz.myBeanMain.postProcessor;

@Slf4j
@Component
public class MyBeanDefinitionRegistryPostProcessor implements BeanDefinitionRegistryPostProcessor
{

    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException
    {
        log.info("chz >>> MyBeanDefinitionRegistryPostProcessor.postProcessBeanDefinitionRegistry():");
        // 修改bean的属性
        BeanDefinition mainBean1 = registry.getBeanDefinition("mainBean1");
        mainBean1.getPropertyValues().add("name", "[mainBean1 - 我被MyBeanDefinitionRegistryPostProcessor改了]");
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException
    {
        log.info("chz >>> MyBeanDefinitionRegistryPostProcessor.postProcessBeanFactory():");
        // 添加一个bean
        MainBean2 mainBean2 = new MainBean2();
        mainBean2.setName(mainBean2.getName() + " - 我是通过MyBeanDefinitionRegistryPostProcessor新加的bean");
        beanFactory.registerSingleton("mainBean2", mainBean2);
    }
}

【MyBeanFactoryPostProcessor.java】

package com.chz.myBeanMain.postProcessor;

@Slf4j
@Component
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor
{
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException
    {
        log.info("chz >>> MyBeanFactoryPostProcessor.postProcessBeanFactory():");
        // 添加一个bean
        MainBean3 mainBean3 = new MainBean3();
        mainBean3.setName(mainBean3.getName() + " - 我是通过MyBeanFactoryPostProcessor新加的bean");
        beanFactory.registerSingleton("mainBean3", mainBean3);
    }
}

【MyBeanPostProcessor.java】

package com.chz.myBeanMain.postProcessor;

@Slf4j
@Component
public class MyBeanPostProcessor implements BeanPostProcessor
{
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        log.info("chz >>> MyBeanPostProcessor.postProcessBeforeInitialization(): {}", beanName);
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException
    {
        log.info("chz >>> MyBeanPostProcessor.postProcessAfterInitialization(): {}", beanName);
        if( (bean instanceof IMainBean4) && !(bean instanceof MainBean4Proxy)){
            // 代码bean
            bean = new MainBean4Proxy((MainBean4)bean);
        }
        return bean;
    }
}

【MyBeanMainTest.java】

package com.chz.myBeanMain;

@SpringBootApplication
public class MyBeanMainTest {

    public static void main(String[] args) {
        SpringApplication.run(MyBeanMainTest.class, args);
    }
}