JavaAgent-agentmain方式

JavaAgent技术的Demo，agentmain方式 采用Javaassist技术实现字节码修改，VirtualMachine技术实现运行时代码织入

package com.reason.demo.attachagent;

import com.sun.tools.attach.VirtualMachine;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;

/**
 * Created by liuruisen on 2018/11/18.
 */
public class AgentAttach {

    private static String agentPath = “/Users/liuruisen/IdeaProjects/javaagent/target/javaagent-1.0-SNAPSHOT.jar“;

    public static void main（String[] args） {

        final ClassLoader classLoader = Thread.currentThread（）.getContextClassLoader（）;
        Class vmClass = null;
        try {
            vmClass = classLoader.loadClass（“com.sun.tools.attach.VirtualMachine“）;
        } catch （ClassNotFoundException e） {
            e.printStackTrace（）;
        }

        object vmobject = null;
        try {
            vmobject = vmClass.getMethod（“attach“ String.class）.invoke（null args[0]）;

            VirtualMachine virtualMachine = （VirtualMachine） vmobject;
            System.out.println（virtualMachine.id（））;

            Method loadAgentMethod = vmClass.getMethod（“loadAgent“ String.class String.class）;

            loadAgentMethod.invoke（vmobject agentPath ““）;
        } catch （IllegalAccessException e） {
            e.printStackTrace（）;
        } catch （InvocationTargetException e） {
            e.printStackTrace（System.out）;
            e.printStackTrace（）;
        } catch （NoSuchMethodException e） {
            e.printStackTrace（）;
        } finally {
            if （null != vmobject） {
                try {
                    vmClass.getMethod（“detach“ （Class[]） null）.invoke（vmobject
                            （object[]） null）;
                    System.out.println（“Detach Success“）;
                } catch （Exception e） {

                }
            }
        }

        try {
            while （true） {
                TimeUnit.SECONDS.sleep（10）;
                System.out.println（“HHAHHAHAH“）;
            }
        } catch （InterruptedException e） {
            if （null != vmobject） {
                try {
                    vmClass.getMethod（“detach“ （Class[]） null）.invoke（vmobject
                            （object[]） null）;
                    System.out.println（“Detach Success“）;
                } catch （Exception exx） {

                }
            }
            e.printStackTrace（）;
        }

    }
}

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2018-12-02 16:49  demo-spring\
     文件        5810  2018-11-06 20:41  demo-spring\mvnw.cmd
     文件        8433  2018-11-28 22:47  demo-spring\demo-spring.iml
     文件        2991  2018-11-28 22:48  demo-spring\pom.xml
     文件         268  2018-11-06 20:41  demo-spring\.gitignore
     目录           0  2018-11-06 20:41  demo-spring\.mvn\
     目录           0  2018-11-06 20:41  demo-spring\.mvn\wrapper\
     文件         116  2018-11-06 20:41  demo-spring\.mvn\wrapper\maven-wrapper.properties
     文件       48337  2018-11-06 20:41  demo-spring\.mvn\wrapper\maven-wrapper.jar
     文件        9113  2018-11-06 20:41  demo-spring\mvnw
     目录           0  2018-12-02 16:50  demo-spring\.idea\
     文件         172  2018-11-06 20:42  demo-spring\.idea\encodings.xml
     目录           0  2018-11-06 20:41  demo-spring\.idea\inspectionProfiles\
     目录           0  2018-11-28 22:47  demo-spring\.idea\libraries\
     文件         673  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__org_apache_tomcat_embed_tomcat_embed_core_9_0_12.xml
     文件         548  2018-11-28 22:47  demo-spring\.idea\libraries\Maven__org_mybatis_mybatis_3_4_6.xml
     文件         583  2018-11-06 20:43  demo-spring\.idea\libraries\Maven__org_xmlunit_xmlunit_core_2_6_2.xml
     文件         621  2018-11-11 17:23  demo-spring\.idea\libraries\Maven__org_apache_logging_log4j_log4j_api_2_11_1.xml
     文件         692  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__com_fasterxml_jackson_core_jackson_annotations_2_9_0.xml
     文件         656  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__org_jboss_logging_jboss_logging_3_3_2_Final.xml
     文件         671  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__com_fasterxml_jackson_core_jackson_databind_2_9_7.xml
     文件         678  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__org_springframework_spring_webmvc_5_1_2_RELEASE.xml
     文件         722  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__com_fasterxml_jackson_datatype_jackson_datatype_jdk8_2_9_7.xml
     文件         685  2018-11-06 20:43  demo-spring\.idea\libraries\Maven__org_springframework_spring_context_5_1_2_RELEASE.xml
     文件         768  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__org_springframework_boot_spring_boot_starter_web_2_1_0_RELEASE.xml
     文件         664  2018-11-06 20:43  demo-spring\.idea\libraries\Maven__org_springframework_spring_test_5_1_2_RELEASE.xml
     文件         789  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__org_springframework_boot_spring_boot_starter_tomcat_2_1_0_RELEASE.xml
     文件         570  2018-11-11 17:24  demo-spring\.idea\libraries\Maven__com_fasterxml_classmate_1_4_0.xml
     文件         657  2018-11-06 20:43  demo-spring\.idea\libraries\Maven__org_springframework_spring_jcl_5_1_2_RELEASE.xml
     文件         580  2018-11-06 20:43  demo-spring\.idea\libraries\Maven__org_hamcrest_hamcrest_core_1_3.xml
     文件         616  2018-11-11 17:23  demo-spring\.idea\libraries\Maven__ch_qos_logback_logback_classic_1_2_3.xml
............此处省略148个文件信息