[JVM]Java生产环境下性能监控与调优详解_Btrace

﹏ヽ暗。殇╰゛Y 2022-05-09 07:26 224阅读 0赞

> 本章关键词：BTrace、拦截、注意事项

## 一、入门 ##

1.做什么的？

*  可以在应用程序不重启，不修改的情况下，正在运行的情况下，动态的修改字节码，达到监控调试的目的
 *  可以动态的向目标应用程序的字节码注入追踪代码
 *  用到的技术

> JavaComplierApi、JVMTI、Agent、Instrumentation+ASM

2.安装

*  到[官网][Link 1]中下载相应版本
 *  新建环境变量BTRACE\_HOME，添加Path:%BTRACE\_HOME%\\bin

> 环境变量的添加请自行百度

*  两种运行脚本方式

1.  JVisualVM中添加Btrace插件（参见上一章），添加classpath

2.使用命令行btrace <pid> <trace\_script>

3.使用详解

*  代码示例  
    btrace需要引入三个jar，就是下载的btrace程序中，build目录下的三个
    
     
    
    ![Image 1][]
    
    jar包.png

引入jar包

<dependency>
                <groupId>com.sun.btrace</groupId>
                <artifactId>btrace-boot</artifactId>
                <version>1.3.11</version>
                <type>jar</type>
                <scope>system</scope>
                <systemPath>D:/btrace-bin-1.3.11/build/btrace-boot.jar</systemPath>
            </dependency>
    
            <dependency>
                <groupId>com.sun.btrace</groupId>
                <artifactId>btrace-agent</artifactId>
                <version>1.3.11</version>
                <type>jar</type>
                <scope>system</scope>
                <systemPath>D:/btrace-bin-1.3.11/build/btrace-agent.jar</systemPath>
            </dependency>
            <dependency>
                <groupId>com.sun.btrace</groupId>
                <artifactId>btrace-client</artifactId>
                <version>1.3.11</version>
                <type>jar</type>
                <scope>system</scope>
                <systemPath>D:/btrace-bin-1.3.11/build/btrace-client.jar</systemPath>
            </dependency>

将要被拦截的代码

package com.qinxianyun.monitor_tuning.chapter4;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * @author Qinxianyun
     * @version V1.0
     * @time 2018/7/21.12:50
     * @description 演示btrace
     */
    @RestController
    @RequestMapping("ch4")
    public class Ch4Controller {
        @RequestMapping("/arg1")
        public String arg1(@RequestParam("name")String name){
            return "hello," + name;
        }
    }

btrace脚本（脚本和代码没有必要关联性，脚本可以随便写在哪里，没有必要写在方法的一个项目里面）

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.AnyType;
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.*;
    
    @BTrace
    public class PrintArgSimple {
       
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter4.Ch4Controller",
                method = "arg1",
                location = @Location(Kind.ENTRY)
        )
        public static void anyRead(@ProbeClassName String pcn, @ProbeMethodName String pmn, AnyType[] args){
            BTraceUtils.printArray(args);
            BTraceUtils.println(pcn + "," + pmn);
            BTraceUtils.println();
        }
    }

> @OnMethod表示我们要拦截哪个类的哪个方法，在什么时候进行拦截  
> Kind.ENTRY表示在入口的时候拦截（也就是一进入方法的时候）  
> @param pcn 拦截方法类的类名  
> @param pmn 拦截方法的方法名  
> @param args 参数

*  进入到btrace脚本的目录下
    
     
    
    ![Image 1][]
    
    进入目录.png
 *  查看进程id
    
     
    
    ![Image 1][]
    
    查看进程id.png
 *  运行脚本文件
    
     
    
    ![Image 1][]
    
    运行中.png
 *  浏览器中输入[http://localhost:8080/ch4/arg1?name=qinxianyun][http_localhost_8080_ch4_arg1_name_qinxianyun]  
    出现如下处理结果
    
    ![Image 1][]
    
    处理结果.png
    
     
 *  Java VisualVM打开btrace（需要已经安装了插件，详情见上一章）
    
     
    
    ![Image 1][]
    
    vm打开btrace.png
    
     
    
    ![Image 1][]
    
    界面详解.png
    
     
    
    ![Image 1][]
    
    输出.png

## 二、拦截构造函数、同名函数 ##

1.拦截方法（普通方法、构造方法、同名方法）

*  普通方法 @OnMethod(clazz=" ",method=" ")

> 参考上面的例子

*  构造函数@OnMethod(clazz=" ",method="<init>")

> 因为构造函数在字节码层面是叫init，所以用<init>

@RequestMapping("/constructor")
        public User arg1(User user){
            return user;
        }

package com.qinxianyun.monitor_tuning.chapter2;
    
    /**
     * @author Qinxianyun
     * @version V1.0
     * @time 2018/7/15.14:52
     * @description 用户实体
     */
    public class User {
        private int id;
    
        private String name;
    
        public User(int id, String name) {
            this.id = id;
            this.name = name;
        }
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    }

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.AnyType;
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.BTrace;
    import com.sun.btrace.annotations.OnMethod;
    import com.sun.btrace.annotations.ProbeClassName;
    import com.sun.btrace.annotations.ProbeMethodName;
    
    @BTrace
    public class PrintConstructor {
    
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter2.User",
                method = "<init>"
        )
        public static void anyRead(@ProbeClassName String pcn, @ProbeMethodName String pmn, AnyType[] args){
            BTraceUtils.println(pcn + "," + pmn);
            BTraceUtils.printArray(args);
            BTraceUtils.println();
        }
    }

![Image 1][]

运行结果.png

*  同名方法（用参数区分）

@RequestMapping("/same1")
        public String same(@RequestParam("name")String name){
            return "hello," + name;
        }
    
        @RequestMapping("/same2")
        public String same(@RequestParam("name")String name,@RequestParam("id")int id){
            return "hello," + name + "," +id;
        }

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.AnyType;
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.BTrace;
    import com.sun.btrace.annotations.OnMethod;
    import com.sun.btrace.annotations.ProbeClassName;
    import com.sun.btrace.annotations.ProbeMethodName;
    
    @BTrace
    public class PrintSame {
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter4.Ch4Controller",
                method = "same"
        )
        public static void anyRead(@ProbeClassName String pcn, @ProbeMethodName String pmn, String name ,int id){
            BTraceUtils.println(pcn + "," + pmn + "," + name + "," + id);
            BTraceUtils.println();
        }
    }

> 拦截重载的方法，是根据参数的类型区分的，脚本中的名字可以和代码中参数名不一致

运行结果：

![Image 1][]

运行结果1.png

## 三、拦截返回值、异常行号 ##

1.拦截时机

*  Kind.ENTRY : 入口，默认值

> 参考第一个例子

*  Kind.RETURN ： 返回

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.AnyType;
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.*;
    
    @BTrace
    public class PrintReturn {
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter4.Ch4Controller",
                method = "arg1",
                location = @Location(Kind.RETURN)
        )
        public static void anyRead(@ProbeClassName String pcn, @ProbeMethodName String pmn, @Return AnyType result){
            BTraceUtils.println(pcn + "," + pmn + "," + result);
            BTraceUtils.println();
        }
    }

*  Kind.THROW ： 异常

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.*;
    
    @BTrace
    public class PrintOnThrow {
        @TLS
        static Throwable currentException;
    
        @OnMethod(
                clazz = "java.lang.Throwable",
                method = "<init>"
        )
        public static void onthrow(@Self Throwable self){//new Throwable()
            currentException = self;
        }
    
        @OnMethod(
                clazz = "java.lang.Throwable",
                method = "<init>"
        )
        public static void onthrow1(@Self Throwable self,String s){//new Throwable(String msg)
            currentException = self;
        }
    
        @OnMethod(
                clazz = "java.lang.Throwable",
                method = "<init>"
        )
        public static void onthrow1(@Self Throwable self,String s,Throwable cause){//new Throwable(String msg,Throwable cause)
            currentException = self;
        }
    
        @OnMethod(
                clazz = "java.lang.Throwable",
                method = "<init>"
        )
        public static void onthrow2(@Self Throwable self,Throwable cause){//new Throwable(Throwable cause)
            currentException = self;
        }
    
        @OnMethod(
                clazz = "java.lang.Throwable",
                method = "<init>",
                location = @Location(Kind.RETURN)
        )
        public static void onthrowreturn(){
            if (currentException != null){
                BTraceUtils.Threads.jstack(currentException);
                BTraceUtils.println("========================");
                currentException = null;
            }
        }
    }

*  Kind.Line ：行

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.*;
    
    @BTrace
    public class PrintLine {
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter4.Ch4Controller",
                location = @Location(value = Kind.LINE,line = 41)
        )
        public static void anyRead(@ProbeClassName String pcn,@ProbeMethodName String pmn,int line){
            BTraceUtils.println(pcn + "," + pmn + "," + line);
            BTraceUtils.println();
        }
    }

## 四、拦截复杂参数、环境变量、正则匹配拦截 ##

1.拦截this、入参、返回

*  this：@Self
 *  入参：可以用AnyType，也可以用真实类型，同名的用真实的
 *  返回：@Return

2.获取对象的值

*  简单类型：直接获取
 *  复杂类型：反射，类名+属性名

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.qinxianyun.monitor_tuning.chapter2.User;
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.*;
    
    import java.lang.reflect.Field;
    
    @BTrace
    public class PrintArgComplex {
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter4.Ch4Controller",
                method = "arg2",
                location = @Location(Kind.ENTRY)
        )
        public static void anyRead(@ProbeClassName String pcn, @ProbeMethodName String pmn, User user){
            BTraceUtils.printFields(user);
            Field field2 = BTraceUtils.field("com.qinxianyun.monitor_tuning.chapter2.User","name");
            BTraceUtils.println(BTraceUtils.get(field2,user));
            BTraceUtils.println(pcn + "," + pmn);
            BTraceUtils.println();
        }
    }

>  
> 
>  
> 
> 注意：
> 
> ![Image 1][]
> 
> 复杂类型.png
> 
>  
> 
> 引用的需要加上-cp

3.正则表达式

*  拦截任意方法

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.*;
    
    @BTrace
    public class PrintRegex {
        @OnMethod(
                clazz = "com.qinxianyun.monitor_tuning.chapter4.Ch4Controller",
                method = "/.*/"
        )
        public static void anyRead(@ProbeClassName String pcn, @ProbeMethodName String pmn){
            BTraceUtils.println(pcn + "," + pmn);
            BTraceUtils.println();
        }
    }

4.打印环境变量

*  打印(输出类似Jinfo命令)

package com.qinxianyun.monitor_tuning.chapter4;
    
    import com.sun.btrace.BTraceUtils;
    import com.sun.btrace.annotations.BTrace;
    
    @BTrace
    public class PrintJinfo {
        static {
            BTraceUtils.println("System Properties:");
            BTraceUtils.printProperties();
            BTraceUtils.println("VM Flags:");
            BTraceUtils.printVmArguments();
            BTraceUtils.println("OS Enviroment:");
            BTraceUtils.printEnv();
            BTraceUtils.exit();
        }
    }

*  输出结果
    
     
    
    ![Image 1][]
    
    输出.png

> 注意事项：  
> 1.默认只能本地运行  
> 2.生产环境下可以使用，但是被修改的字节码不会被还原（即使btrace退出）  
> 因此，脚本中不要有太耗系统资源的东西，否则会影响服务器。

[Link 1]: https://github.com/btraceio/btrace/releases/tag/v1.3.11
[Image 1]: 
[http_localhost_8080_ch4_arg1_name_qinxianyun]: http://localhost:8080/ch4/arg1?name=qinxianyun