new操作时调用当前线程的类加载器，还是调用方的类加载器 （四）完美证明用例

 

 

A cl1
{
	new thread().setClassLoader(cl2)
	new cl3 -> new B
 	b.func {
		C c = new C
	}
}

　　

三个类加载器把C纳入可见范围内
1 A C
2 C
3 B C

/Users/joyce/work/MyTest/ClWhichClassLoader/ClWhich/src/main/java/com/demolc/TestMain.java

 

ClCaller.A

package com.demolc;

import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.List;

/**
 * Created by joyce on 2022/6/29.
 */
public class A {
    public void func() throws Exception {
        String urlThread = "file:/Users/joyce/work/MyTest/ClWhichClassLoader/ClThread/target/ClThread-1.0.0-jar-with-dependencies.jar";
        URLClassLoader clThread = new URLClassLoader(new URL[]{new URL(urlThread)});
        Thread thread = new Thread(new MyThread());
        thread.setContextClassLoader(clThread);
        thread.start();

    }

    private static class MyThread implements Runnable {

        @Override
        public void run() {
            String urlLast = "file:/Users/joyce/work/MyTest/ClWhichClassLoader/ClLast/target/ClLast-1.0.0-jar-with-dependencies.jar";
            try {
                URLClassLoader clLast = new URLClassLoader(new URL[]{new URL(urlLast)});
                Class cB = clLast.loadClass("com.demolc.B");
                Method method = cB.getMethod("func");
                method.invoke(cB.newInstance());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

 

主

package com.demolc;

import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;

/**
 * 证明C c=new C调用this.getClass().getClassLoader
 * 前提：让com.demolc.C对3个类加载器可见
 * Chttps://www.cnblogs.com/silyvin/articles/16423447.html
 */
public class TestMain {

    public static void main(String[] f) throws Exception {
        String urlCaller = "file:/Users/joyce/work/MyTest/ClWhichClassLoader/ClCaller/target/ClCaller-1.0.0-jar-with-dependencies.jar";
        URLClassLoader clCaller = new URLClassLoader(new URL[]{new URL(urlCaller)});
        Class cA = clCaller.loadClass("com.demolc.A");
        Method method = cA.getMethod("func");
        method.invoke(cA.newInstance());
    }
}

 

<?xml version="1.0" encoding="UTF-8"?>

<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.sunyuming</groupId>
  <artifactId>ClWhich</artifactId>
  <version>1.0.0</version>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <configuration>
          <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
          </descriptorRefs>
          <archive>
            <!--<manifest>-->
              <!--<mainClass>agent.AgentClient</mainClass>-->
            <!--</manifest>-->
          </archive>
        </configuration>
        <executions>
          <execution>
            <id>make-assembly</id>
            <phase>package</phase>
            <goals>
              <goal>single</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>