Java 应用监控利器

获取方法参数以及返回值

业务代码：

public String sayHello(String name, int age) {
   return "hello everyone";
}

BTrace代码：

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

@BTrace
public class Btrace {

   @OnMethod(
       clazz = "com.jiuyan.message.controller.AdminController",
       method = "sayHello",
       location = @Location(Kind.RETURN)//函数返回的时候执行，如果不填，则在函数开始的时候执行
   )
   public static void sayHello(String name, int age, @Return String result) {
       println("name: " + name);
       println("age: " + age);
       println(result);
   }

}

调用sayHello('mountain', 1)，输出应该是：

name: mountain
age: 1
hello everyone

可以对字符串进行正则匹配以达到监控特定问题的目的：

if(BTraceUtils.matches(".*345.*", str)) {
    println(str);
}

计算方法运行消耗的时间

BTrace代码：

import java.util.Date;

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

@BTrace
public class Btrace {

   @OnMethod(
       clazz = "com.jiuyan.message.controller.AdminController",
       method = "sayHello",
       location = @Location(Kind.RETURN)
   )
   public static void sayHello(@Duration long duration) {//单位是纳秒，要转为毫秒
       println(strcat("duration(ms): ", str(duration / 1000000)));
   }

}