SpringBean和Controller实现动态注册与注销过程详细讲解

时间:2023-03-20 小时候的阳光人气:0

部分场景下可能需要下载远程jar包，然后注册jar包中的Bean和Controller

说明

这里的Bean 一般特指 Service层的服务类，Controller本质上也是Bean

注册和注销工具类

这里用了一些 hutool的工具类，hutools是一个不错的基础工具集。

package cn.guzt.utils;
import cn.hutool.extra.spring.SpringUtil;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
import java.lang.reflect.Method;
/**
 * 动态注册注销Spring Bean
 *
 * @author guzt
 */
@SuppressWarnings("unused")
public class DynamicRegistUtil {
    /**
     * 动态注册Bean
     *
     * @param beanName    bean名称
     * @param targetClass bean对应的类
     */
    public static void registerBeanDefinition(String beanName, Class<?> targetClass) {
        ApplicationContext applicationContext = SpringUtil.getApplicationContext();
        //获取BeanFactory
        DefaultListableBeanFactory defaultListableBeanFactory =
                (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
        //创建bean信息.
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(targetClass);
        //动态注册bean.
        defaultListableBeanFactory.registerBeanDefinition(beanName, beanDefinitionBuilder.getBeanDefinition());
    }
    /**
     * 动态卸载Bean
     *
     * @param beanName bean名称
     */
    public static void unRegisterBeanDefinition(String beanName) {
        ApplicationContext applicationContext = SpringUtil.getApplicationContext();
        if (!applicationContext.containsBean(beanName)) {
            return;
        }
        //获取BeanFactory
        DefaultListableBeanFactory defaultListableBeanFactory =
                (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
        defaultListableBeanFactory.removeBeanDefinition(beanName);
    }
    /**
     * 动态注册Controller
     *
     * @param controllerBeanName controller的beanName
     * @throws Exception 反射异常
     */
    public static void registerController(String controllerBeanName)
            throws Exception {
        final RequestMappingHandlerMapping requestMappingHandlerMapping =
                SpringUtil.getBean(RequestMappingHandlerMapping.class);
        if (requestMappingHandlerMapping != null) {
            Object controller = SpringUtil.getBean(controllerBeanName);
            if (controller == null) {
                return;
            }
            //注册Controller
            Method method = requestMappingHandlerMapping.getClass().getSuperclass().getSuperclass().
                    getDeclaredMethod("detectHandlerMethods", Object.class);
            //将private改为可使用
            method.setAccessible(true);
            method.invoke(requestMappingHandlerMapping, controllerBeanName);
        }
    }
    /**
     * 动态去掉Controller的Mapping
     *
     * @param controllerBeanName controller的beanName
     */
    public static void unregisterController(String controllerBeanName) {
        final RequestMappingHandlerMapping requestMappingHandlerMapping
                = SpringUtil.getBean("requestMappingHandlerMapping");
        if (requestMappingHandlerMapping != null) {
            Object controller = SpringUtil.getBean(controllerBeanName);
            if (controller == null) {
                return;
            }
            final Class<?> targetClass = controller.getClass();
            ReflectionUtils.doWithMethods(targetClass, method -> {
                Method specificMethod = ClassUtils.getMostSpecificMethod(method, targetClass);
                try {
                    Method createMappingMethod = RequestMappingHandlerMapping.class.
                            getDeclaredMethod("getMappingForMethod", Method.class, Class.class);
                    createMappingMethod.setAccessible(true);
                    RequestMappingInfo requestMappingInfo = (RequestMappingInfo)
                            createMappingMethod.invoke(requestMappingHandlerMapping, specificMethod, targetClass);
                    if (requestMappingInfo != null) {
                        requestMappingHandlerMapping.unregisterMapping(requestMappingInfo);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }, ReflectionUtils.USER_DECLARED_METHODS);
        }
    }
}

编写测试用例

创建一个maven项目(dynamic-regist-bean)，里面主要引入spring-boot-starter-web即可

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

创建一个service测试类

package org.example.service;
public interface DynamicRegistService {
    void serviceDo();
}

创建接口对应的实现类，上面无需@Service 注解

package org.example.service.impl;
import lombok.extern.slf4j.Slf4j;
import org.example.service.DynamicRegistService;
@Slf4j
public class DynamicRegistServiceImpl implements DynamicRegistService {
    @Override
    public void serviceDo() {
        log.info("Spring动态注册的Bean dynamicRegistServiceImpl中的 serviceDo 无参方法执行完成...");
    }
}

创建一个controller测试类，类上面无需 @Controller注解

package org.example.controller;
import org.springframework.web.bind.annotation.*;
import java.util.HashMap;
import java.util.Map;
@ResponseBody
@RequestMapping("dynamicRegistController")
public class DynamicRegistController {
    @PostMapping("postTest")
    public Map<String, Object> postTest(@RequestBody Map<String, Object> params) {
        Map<String, Object> map = new HashMap<>(4);
        map.put("code", "0");
        map.put("msg", "POST请求测试成功, 传递参数params:" + params.toString());
        map.put("data", "");
        return map;
    }
    @GetMapping("getTest/{id}")
    public Map<String, Object> getTest(@PathVariable("id") String id) {
        Map<String, Object> map = new HashMap<>(4);
        map.put("code", "0");
        map.put("msg", "GET请求测试成功, 传输的参数id:" + id);
        map.put("data", "");
        return map;
    }
}

编译打包

> maven clean package

mavne打包命令生成 dynamic-regist-bean.jar

另外一个SpringBoot中创建测试接口

假设访问BaseUrl为： http://localhost:8081

import cn.guzt.utils.DynamicRegistUtil;
import cn.hutool.core.util.ClassLoaderUtil;
import cn.hutool.core.util.ReflectUtil;
import cn.hutool.extra.spring.SpringUtil;
import com.middol.starter.common.pojo.vo.NoBody;
import com.middol.starter.common.pojo.vo.ResponseVO;
import io.swagger.annotations.Api;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.io.File;
@Api(tags = "动态注册Bean、Controller测试")
@RestController
@RequestMapping("dynamicRegistTestController")
public class DynamicRegistTestController {
    private static final Logger logger = LoggerFactory.getLogger(DynamicRegistTestController.class);
    /**
     * 模拟从远程下载准备要注册Bean的jar文件
     *
     * @return jar文件
     */
    private File getRmoteJarFile() {
        return new File("E:/IDEA_HOME/dynamic-regist-bean/dynamic-regist-bean/target/dynamic-regist-bean.jar");
    }
    @GetMapping("registBean")
    public ResponseVO<NoBody> registBean() {
        File jarFile = getRmoteJarFile();
        // 准备要注册的Bean类名
        String className = "org.example.service.impl.DynamicRegistServiceImpl";
        // 准备要注册的Bean名称
        String beanName = "dynamicRegistServiceImpl";
        // 注册完成后调用Bean的测试方法
        String invokeMethod = "serviceDo";
        Class<?> targetClass = ClassLoaderUtil.loadClass(jarFile, className);
        logger.info("本次要注册的bean className = {}", targetClass.getName());
        DynamicRegistUtil.registerBeanDefinition(beanName, targetClass);
        Object object = SpringUtil.getBean(beanName);
        ReflectUtil.invoke(object, invokeMethod);
        return ResponseVO.success();
    }
    @GetMapping("unRegistBean")
    public ResponseVO<NoBody> unRegistBean() {
        String beanName = "dynamicRegistServiceImpl";
        logger.info("本次要卸载的bean beanName = {}", beanName);
        DynamicRegistUtil.unRegisterBeanDefinition(beanName);
        logger.info("卸载结果：{}", SpringUtil.getApplicationContext().containsBean(beanName) ? "失败" : "成功");
        return ResponseVO.success();
    }
    @GetMapping("registController")
    public ResponseVO<NoBody> registController() throws Exception {
        File jarFile = getRmoteJarFile();
        // 准备要注册的Bean类名
        String className = "org.example.controller.DynamicRegistController";
        // 准备要注册的Bean名称
        String beanName = "dynamicRegistController";
        Class<?> targetClass = ClassLoaderUtil.loadClass(jarFile, className);
        logger.info("本次要注册的controller className = {}", targetClass.getName());
        DynamicRegistUtil.registerBeanDefinition(beanName, targetClass);
        DynamicRegistUtil.registerController(beanName);
        return ResponseVO.success();
    }
    @GetMapping("unRegistController")
    public ResponseVO<NoBody> unRegistController() {
        String beanName = "dynamicRegistController";
        logger.info("本次要卸载的Controller beanName = {}", beanName);
        DynamicRegistUtil.unregisterController(beanName);
        DynamicRegistUtil.unRegisterBeanDefinition(beanName);
        logger.info("卸载结果：{}", SpringUtil.getApplicationContext().containsBean(beanName) ? "失败" : "成功");
        return ResponseVO.success();
    }
}

测试结果

注册Service

访问： http://localhost:8081/dynamicRegistTestController/registBean

{"code":"0","message":"SUCCESS","data":null}

日志：

[http-nio-8081-exec-1] c.g.c.DynamicRegistTestController : 本次要注册的bean className = org.example.service.impl.DynamicRegistServiceImpl
[http-nio-8081-exec-1] o.e.s.impl.DynamicRegistServiceImpl : Spring动态注册的Bean dynamicRegistServiceImpl中的 serviceDo 无参方法执行完成...

注册controller

访问：http://localhost:8081/dynamicRegistTestController/registController

{"code":"0","message":"SUCCESS","data":null}

日志：

[http-nio-8081-exec-5] c.g.c.DynamicRegistTestController : 本次要注册的controller className = org.example.controller.DynamicRegistController

测试Controller 是否真的注册成功：

访问： http://localhost:8081/dynamicRegistController/getTest/aaaa 返回：

{"msg":"GET请求测试成功, 传输的参数id:aaaa","data":"","code":"0"}

注销Controller

访问：http://localhost:8081/dynamicRegistTestController/unRegistController

然后重新访问： http://localhost:8081/dynamicRegistController/getTest/aaaa

返回：404错误，说明注销成功！

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Feb 07 14:14:52 CST 2023
There was an unexpected error (type=Not Found, status=404).

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