jinfo 干涉java runtime的jvm参数

Posted 2021-12-11 tekikesyo

https://blog.csdn.net/bolg_hero/article/details/78156311

jinfo使用介绍
可以用来查看正在运行的Java应用程序的扩展参数，甚至支持在运行时，修改部分参数

-flag <name> pid：打印指定JVM的参数值 
-flag [+|-]<name> pid：设置指定JVM参数的布尔值
-flag <name>=<value> pid：设置指定JVM参数的值

 

启动GC输出
jinfo   -flag +PrintGC pid
jinfo   -flag +PrintGCDetails pid
jinfo   -flag +PrintGCTimeStamps pid
jinfo   -flag +PrintGCDateStamps pid

------------------------------------------------------------------------------------------------

>jinfo
Usage:
    jinfo [option] <pid>
        (to connect to running process)
    jinfo [option] <executable <core>
        (to connect to a core file)
    jinfo [option] [[email protected]]<remote server IP or hostname>
        (to connect to remote debug server)

where <option> is one of:
    -flag <name>         to print the value of the named VM flag
    -flag [+|-]<name>    to enable or disable the named VM flag
    -flag <name>=<value> to set the named VM flag to the given value
    -flags               to print VM flags
    -sysprops            to print Java system properties
    <no option>          to print both of the above
    -h | -help           to print this help message

看了一下, 基本上市可以设置JVM参数, 而sysprops是没法改的, 只能读取

测试一下:

public class TestMe {
    public static void main(String[] args) {
        System.setProperty("abc", "123");
        while (true) {
            try {
                Thread.sleep(3000L);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(123);
        }
    }
}

挺好~~