// TestController.java

 package com.remotedebug.controller;

 import com.remotedebug.service.IRedisCacheService;

 import org.springframework.beans.factory.annotation.Autowired;

 import org.springframework.web.bind.annotation.RequestMapping;

 import org.springframework.web.bind.annotation.RequestParam;

 import org.springframework.web.bind.annotation.RestController;

 /**

  * desc:

  * 测试接口，模拟从redis中获取缓存。当然，实际场景下，看缓存可以直接用工具的，这里就是举个栗子

  * @author : caokunliang

  * creat_date: 2019/6/18 0018

  * creat_time: 10:13

  **/

 @RestController

 public class TestController {

     @Autowired

     private IRedisCacheService iRedisCacheService;

     /**

      * 缓存获取接口

      * @param cacheKey

      */

     @RequestMapping("getCache.do")

     public String getCache(@RequestParam String  cacheKey){

         String value = iRedisCacheService.getCache(cacheKey);

         System.out.println(value);

         return value;

     }

 }

 // IRedisCacheServiceImpl.java

 package com.remotedebug.service.impl;

 import com.remotedebug.service.IRedisCacheService;

 import lombok.extern.slf4j.Slf4j;

 import org.springframework.stereotype.Service;

 import java.util.List;

 /**

  * desc:

  *

  * @author : caokunliang

  * creat_date: 2019/6/18 0018

  * creat_time: 10:17

  **/

 @Service

 @Slf4j

 public class IRedisCacheServiceImpl implements IRedisCacheService {

     @Override

     public String getCache(String cacheKey) {

23         String target = null;

         // ----------------------前面有复杂逻辑--------------------------

         String count = getCount(cacheKey);

         // ----------------------后面有复杂逻辑，包括对 count 进行修改--------------------------

         if (Integer.parseInt(count) > 1){

             target = "abc";

         }else {

             // 一些业务逻辑，但是忘记给 target 赋值

             // .....

         }

         return target.trim();

     }

     @Override

     public String getCount(String cacheKey){

         // 假设是从redis 读取缓存,这里简单起见，假设value的值就是cacheKey

         return cacheKey;

     }

 }

import com.remotedebug.service.IRedisCacheService;

import com.remotedebug.utils.SpringContextUtils;

import lombok.extern.slf4j.Slf4j;

@Slf4j

public class RemoteDebugTest {

    public void debug(){

        IRedisCacheService bean = SpringContextUtils.getBean(IRedisCacheService.class);

        String value = bean.getCount("user.count.userIdxxx");

        log.info("value:{}", value );

    }

    public static void main(String[] args) {

        new RemoteDebugTest().debug();

    }

}

[root@localhost apache-tomcat-8.0.41]# ll webapps/

total 9336

drwxr-xr-x. 14 root root    4096 Jun 19 11:39 docs

drwxr-xr-x.  6 root root    4096 Jun 19 11:39 examples

drwxr-xr-x.  5 root root    4096 Jun 19 11:39 host-manager

drwxr-xr-x.  5 root root    4096 Jun 19 11:39 manager

drwxr-xr-x.  4 root root    4096 Jun 19 13:48 remotedebug

-rw-r--r--.  1 root root 9531510 Jun 19 13:47 remotedebug.war

drwxr-xr-x.  3 root root    4096 Jun 19 11:39 ROOT

    public void debug(){

        IRedisCacheService bean = SpringContextUtils.getBean(IRedisCacheService.class);

        String value = bean.getCount("123456789");

        log.info("value:{}", value );

    }

 /**

      * 远程debug，读取参数中的class文件的路径，然后加载，并执行其中的方法

      */

     @RequestMapping("/remoteDebugByUploadFile.do")

     @ResponseBody

     public String remoteDebugByUploadFile(@RequestParam String className, @RequestParam String methodName, MultipartFile file) throws Exception {

         if (className == null || file == null || methodName == null) {

             throw new RuntimeException("className,file,methodName must be set");

         }

         /**

          * 获取当前类加载器，当前类肯定是放在webapp的web-inf下的classes，这个类所以是由 webappclassloader 加载的，所以这里获取的就是这个

          */

         ClassLoader webappClassloader = this.getClass().getClassLoader();

         log.info("webappClassloader:{}",webappClassloader);

         /**

          * 用自定义类加载器，加载参数中指定的class文件，并执行其方法

          */

         log.info("开始执行:{}中的方法:{}",className,methodName);

         InputStream inputStream = file.getInputStream();

         UploadFileStreamClassLoader myClassLoader = new UploadFileStreamClassLoader(inputStream, className, webappClassloader);

         Class<?> myDebugClass = myClassLoader.loadClass(className);

         MyReflectionUtils.invokeMethodOfClass(myDebugClass, methodName);

         log.info("结束执行:{}中的方法:{}",className,methodName);

         return "success";

     }

 package com.remotedebug.utils;

 import lombok.extern.slf4j.Slf4j;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.UnsupportedEncodingException;

 import java.net.URL;

 import java.net.URLConnection;

 /**

  * desc:

  *

  * @author : caokunliang

  * creat_date: 2019/6/13 0013

  * creat_time: 10:19

  **/

 @Slf4j

 public class UploadFileStreamClassLoader extends ClassLoader {

     /**

      * 要加载的class的类名

      */

     private String className;

     /**

      * 要加载的调试class的流，可以通过客户端文件上传，也可以通过传递url来获取

      */

     private InputStream inputStream;

     /**

      *

      * @param inputStream 要加载的class 的文件流

      * @param className 类名

      * @param parentWebappClassLoader 父类加载器

      */

     public UploadFileStreamClassLoader(InputStream inputStream, String className, ClassLoader parentWebappClassLoader) {

         super(parentWebappClassLoader);

         this.className = className;

         this.inputStream = inputStream;

     }

     @Override

     protected Class<?> findClass(String name) throws ClassNotFoundException {

46         byte[] data = getData();

         try {

             String s = new String(data, "utf-8");

 //            log.info("class content:{}",s);

         } catch (UnsupportedEncodingException e) {

             e.printStackTrace();

         }

54         return defineClass(className,data,0,data.length);

     }

     private byte[] getData(){

         try {

             ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

             byte[] bytes = new byte[2048];

             int num = 0;

             while ((num = inputStream.read(bytes)) != -1){

                 byteArrayOutputStream.write(bytes, 0,num);

             }

             return byteArrayOutputStream.toByteArray();

         } catch (Exception e) {

             log.error("read stream failed.{}",e);

             throw new RuntimeException(e);

         }

     }

 }

 1 import com.remotedebug.service.IRedisCacheService;

 2 import com.remotedebug.utils.SpringContextUtils;

 3 import lombok.extern.slf4j.Slf4j;

 @Slf4j

 public class RemoteDebugTest {

     public void debug(){

         IRedisCacheService bean = SpringContextUtils.getBean(IRedisCacheService.class);

         String value = bean.getCount("123456789");

         log.info("value:{}", value );

     }

 }

    <bean

          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

        <property name="defaultEncoding" value="utf-8" />

        <property name="maxUploadSize" value="10485760000" />

        <property name="maxInMemorySize" value="40960" />

    </bean>

    <servlet>

        <servlet-name>DispatcherServlet</servlet-name>

        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

        <init-param>

            <param-name>contextConfigLocation</param-name>

            <param-value>classpath*:/remotedebug-servlet.xml</param-value>

        </init-param>

        <load-on-startup>1</load-on-startup>

        <multipart-config>

            <location></location>

            <max-file-size>20848820</max-file-size>

            <max-request-size>418018841</max-request-size>

            <file-size-threshold>1048576</file-size-threshold>

        </multipart-config>

    </servlet>