在程序运行期间，注入调试代码，注入代码对程序变量只读,且不能调用函数 ===== 使用方法 ===== - 下载btrace程序 - 查找要注入的程序的pid - 编写btrace代码 - 开始注入~/Downloads/btrace-bin-1.3.5/bin/btrace 48650 TraceMethodArgsAndReturn.java - 48650 是主程序的pid ==== maven ====


     
            com.sun.tools.btrace
            btrace-agent
            1.0.5
        
        
            com.sun.tools.btrace
            btrace-boot
            1.0.5

==== main ====


import java.util.Random;

public class CaseObject {

    private static int sleepTotalTime = 0;

    public static void main(String[] args) throws Exception {
        Random random = new Random();
        CaseObject object = new CaseObject();
        boolean result = true;
        while (result) {
            result = object.execute(random.nextInt(1000));
            Thread.sleep(1000);
        }
    }

    public boolean execute(int sleepTime) throws Exception {
        System.out.println("sleep: " + sleepTime);
        sleepTotalTime += sleepTime;
        Thread.sleep(sleepTime);
        return true;
    }
}

==== btrace ====


import static com.sun.btrace.BTraceUtils.*;
import com.sun.btrace.annotations.*;

@BTrace public class TraceMethodArgsAndReturn{
    @OnMethod(
            clazz="CaseObject",
            method="execute",
            location=@Location(Kind.RETURN)
    )

    public static void traceExecute(@Self Object instance,int sleepTime,@Return boolean result){
        println("call CaseObject.execute");
        println(strcat("sleepTime is:", str(sleepTime)));
        // 获取类的属性
        int field = (Integer) get(field("CaseObject", "sleepTotalTime"), instance);
        println("sleepTotalTime is:"+field);
        println(strcat("return value is:", str(result)));
        // 查看调用栈
        jstack();
    }
}