java-agent 例子

记录一下java-agent 例子

java code:

package test;

import java.lang.instrument.Instrumentation;

public class TestAgent {

    public static void premain(String options, Instrumentation inst) {
        System.out.println("begin do premain");
        init();
    }

    public static void init() {
        AppContext.init();
    }
}

package test;

public class AppContext {

    private static String app_id;

    public static String getAppId() {
        return app_id;
    }

    public static void init() {
        app_id = "my-agent";
    }
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.demo.biz</groupId>
  <artifactId>my-agent</artifactId>
  <version>0.0.1-SNAPSHOT</version>


  <build>
        <plugins>
           <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.0.2</version>
                <configuration>
                    <archive>
                        <manifestEntries>
                            <Premain-Class>test.TestAgent</Premain-Class>
                        </manifestEntries>
                    </archive>
                </configuration>
            </plugin>

        </plugins>
    </build>


</project>