/** 
 *   測試程序
 * @author zhangyu
 * @date 2022/2/17
*/
@SpringBootApplication
@RestController
public class DebuggerApplication {

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

    @GetMapping("/test")
    public  String test(){
        System.out.println(111);
        System.out.println(222);
        return "OK";
    }

}

java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8888 -jar debugger-0.0.1-SNAPSHOT.jar

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class DebuggerApplication {

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

    @GetMapping("/test")
    public  String test(String name){
        System.out.println("進入方法");
        int var=100;
        System.out.println(name);
        System.out.println(var);
        System.out.println("方法結束");
        return "OK";
    }
}

import com.sun.jdi.*;
import com.sun.jdi.connect.AttachingConnector;
import com.sun.jdi.connect.Connector;
import com.sun.jdi.event.*;
import com.sun.jdi.request.BreakpointRequest;
import com.sun.jdi.request.EventRequest;
import com.sun.jdi.request.EventRequestManager;
import com.sun.tools.jdi.SocketAttachingConnector;

import java.util.List;
import java.util.Map;

/**
 *  通過JNI工具測試Debug
 * @author zhangyu
 * @date 2022/2/20
*/
public class TestDebugVirtualMachine {


    private static VirtualMachine vm;

    public static void main(String[] args) throws Exception {
        //獲取SocketAttachingConnector,連接其它JVM稱之為附加(attach)操作
        VirtualMachineManager vmm = Bootstrap.virtualMachineManager();
        List<AttachingConnector> connectors = vmm.attachingConnectors();
        SocketAttachingConnector sac = null;
        for(AttachingConnector ac : connectors) {
            if(ac instanceof SocketAttachingConnector) {
                sac = (SocketAttachingConnector) ac;
            }
        }
        assert sac != null;
        //設置好主機地址，端口信息
        Map<String, Connector.Argument> arguments = sac.defaultArguments();
        Connector.Argument hostArg = arguments.get("hostname");
        Connector.Argument portArg = arguments.get("port");
        hostArg.setValue("127.0.0.1");
        portArg.setValue(String.valueOf(8800));
        //進行連接
         vm = sac.attach(arguments);
        //相應的請求調用通過requestManager來完成
        EventRequestManager eventRequestManager = vm.eventRequestManager();
        //創(chuàng)建一個代碼判斷，因此需要獲取相應的類，以及具體的斷點位置，即相應的代碼行。
        ClassType clazz = (ClassType) vm.classesByName("com.zy.debugger.DebuggerApplication").get(0);
        //設置斷點代碼位置
        Location location = clazz.locationsOfLine(22).get(0);
        //創(chuàng)建新斷點并設置阻塞模式為線程阻塞，即只有當前線程被阻塞
        BreakpointRequest breakpointRequest = eventRequestManager.createBreakpointRequest(location);
        //設置阻塞并啟動
        breakpointRequest.setSuspendPolicy(EventRequest.SUSPEND_EVENT_THREAD);
        breakpointRequest.enable();
        //獲取vm的事件隊列
        EventQueue eventQueue = vm.eventQueue();
        while(true) {
            //不斷地讀取事件并處理斷點記錄事件
            EventSet eventSet = eventQueue.remove();
            EventIterator eventIterator = eventSet.eventIterator();
            while(eventIterator.hasNext()) {
                Event event = eventIterator.next();
                execute(event);
            }
            //將相應線程resume，表示繼續(xù)運行
            eventSet.resume();
        }
    }

    /**
     *  處理監(jiān)聽到事件
     * @author zhangyu
     * @date 2022/2/20
    */
    public static void execute(Event event) throws Exception {
        //獲取的event為一個抽象的事件記錄，可以通過類型判斷轉型為具體的事件，這里我們轉型為BreakpointEvent，即斷點記錄，
        BreakpointEvent breakpointEvent = (BreakpointEvent) event;
        //并通過斷點處的線程拿到線程幀，進而獲取相應的變量信息，并打印記錄。
        ThreadReference threadReference = breakpointEvent.thread();
        StackFrame stackFrame = threadReference.frame(0);
        List<LocalVariable> localVariables = stackFrame.visibleVariables();
        //輸出當前線程棧幀保存的變量數(shù)據(jù)
        localVariables.forEach(t -> {
            Value value = stackFrame.getValue(t);
            System.out.println("local->" + value.type() + "," + value.getClass() + "," + value);
        });
    }

}