SpringBean和Controller實現動態註冊與登出過程詳細講解

2023-02-10 06:00:58

說明

這裡的Bean 一般特指 Service層的服務類，Controller本質上也是Bean

註冊和登出工具類

這裡用了一些 hutool的工具類，hutools是一個不錯的基礎工具集。

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;
/**
 * 動態註冊登出Spring Bean
 *
 * @author guzt
 */
@SuppressWarnings("unused")
public class DynamicRegistUtil {
    /**
     * 動態註冊Bean
     *
     * @param beanName    bean名稱
     * @param targetClass bean對應的類
     */
    public static void registerBeanDefinition(String beanName, Class<?> targetClass) {
        ApplicationContext applicationContext = SpringUtil.getApplicationContext();
        //獲取BeanFactory
        DefaultListableBeanFactory defaultListableBeanFactory =
                (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
        //建立bean資訊.
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(targetClass);
        //動態註冊bean.
        defaultListableBeanFactory.registerBeanDefinition(beanName, beanDefinitionBuilder.getBeanDefinition());
    }
    /**
     * 動態解除安裝Bean
     *
     * @param beanName bean名稱
     */
    public static void unRegisterBeanDefinition(String beanName) {
        ApplicationContext applicationContext = SpringUtil.getApplicationContext();
        if (!applicationContext.containsBean(beanName)) {
            return;
        }
        //獲取BeanFactory
        DefaultListableBeanFactory defaultListableBeanFactory =
                (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
        defaultListableBeanFactory.removeBeanDefinition(beanName);
    }
    /**
     * 動態註冊Controller
     *
     * @param controllerBeanName controller的beanName
     * @throws Exception 反射異常
     */
    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;
            }
            //註冊Controller
            Method method = requestMappingHandlerMapping.getClass().getSuperclass().getSuperclass().
                    getDeclaredMethod("detectHandlerMethods", Object.class);
            //將private改為可使用
            method.setAccessible(true);
            method.invoke(requestMappingHandlerMapping, controllerBeanName);
        }
    }
    /**
     * 動態去掉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);
        }
    }
}

編寫測試用例

建立一個maven專案(dynamic-regist-bean)，裡面主要引入spring-boot-starter-web即可

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

建立一個service測試類

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

建立介面對應的實現類，上面無需@Service 註解

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動態註冊的Bean dynamicRegistServiceImpl中的 serviceDo 無參方法執行完成...");
    }
}

建立一個controller測試類，類上面無需 @Controller註解

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請求測試成功, 傳遞引數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請求測試成功, 傳輸的引數id:" + id);
        map.put("data", "");
        return map;
    }
}

編譯打包

> maven clean package

mavne打包命令生成 dynamic-regist-bean.jar

另外一個SpringBoot中建立測試介面

假設存取BaseUrl為： 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 = "動態註冊Bean、Controller測試")
@RestController
@RequestMapping("dynamicRegistTestController")
public class DynamicRegistTestController {
    private static final Logger logger = LoggerFactory.getLogger(DynamicRegistTestController.class);
    /**
     * 模擬從遠端下載準備要註冊Bean的jar檔案
     *
     * @return jar檔案
     */
    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();
        // 準備要註冊的Bean類名
        String className = "org.example.service.impl.DynamicRegistServiceImpl";
        // 準備要註冊的Bean名稱
        String beanName = "dynamicRegistServiceImpl";
        // 註冊完成後呼叫Bean的測試方法
        String invokeMethod = "serviceDo";
        Class<?> targetClass = ClassLoaderUtil.loadClass(jarFile, className);
        logger.info("本次要註冊的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("本次要解除安裝的bean beanName = {}", beanName);
        DynamicRegistUtil.unRegisterBeanDefinition(beanName);
        logger.info("解除安裝結果：{}", SpringUtil.getApplicationContext().containsBean(beanName) ? "失敗" : "成功");
        return ResponseVO.success();
    }
    @GetMapping("registController")
    public ResponseVO<NoBody> registController() throws Exception {
        File jarFile = getRmoteJarFile();
        // 準備要註冊的Bean類名
        String className = "org.example.controller.DynamicRegistController";
        // 準備要註冊的Bean名稱
        String beanName = "dynamicRegistController";
        Class<?> targetClass = ClassLoaderUtil.loadClass(jarFile, className);
        logger.info("本次要註冊的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("本次要解除安裝的Controller beanName = {}", beanName);
        DynamicRegistUtil.unregisterController(beanName);
        DynamicRegistUtil.unRegisterBeanDefinition(beanName);
        logger.info("解除安裝結果：{}", SpringUtil.getApplicationContext().containsBean(beanName) ? "失敗" : "成功");
        return ResponseVO.success();
    }
}

測試結果

註冊Service

存取： http://localhost:8081/dynamicRegistTestController/registBean

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

紀錄檔：

[http-nio-8081-exec-1] c.g.c.DynamicRegistTestController : 本次要註冊的bean className = org.example.service.impl.DynamicRegistServiceImpl
[http-nio-8081-exec-1] o.e.s.impl.DynamicRegistServiceImpl : Spring動態註冊的Bean dynamicRegistServiceImpl中的 serviceDo 無參方法執行完成...

註冊controller

存取：http://localhost:8081/dynamicRegistTestController/registController

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

紀錄檔：

[http-nio-8081-exec-5] c.g.c.DynamicRegistTestController : 本次要註冊的controller className = org.example.controller.DynamicRegistController

測試Controller 是否真的註冊成功：

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

{"msg":"GET請求測試成功, 傳輸的引數id:aaaa","data":"","code":"0"}

登出Controller

存取：http://localhost:8081/dynamicRegistTestController/unRegistController

然後重新存取： http://localhost:8081/dynamicRegistController/getTest/aaaa

返回：404錯誤，說明登出成功！

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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