package com.an.classloadertest;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
/**
* @author apy
* @description
* @date 2022/3/9 16:44
*/
public class TestMain {
private String name;
private String job;
public String getJob() {
return job;
}
public String getName() {
return name;
}
public void setJob(String job) {
this.job = job;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "TestMain{" +
"name='" + name + '\'' +
", job='" + job + '\'' +
'}';
}
public static void main(String[] args) throws IOException, IllegalAccessException, InstantiationException, ClassNotFoundException {
// TestMain.class.getResource("/") 与 testMain.getClass().getClassLoader().getResource("") 路径一致
// test();
// classTest();
// classLoaderTest1();
// classLoaderTest();
// scanPackage();
}
private static void scanPackage() throws IOException, ClassNotFoundException, IllegalAccessException, InstantiationException {
TestMain testMain = new TestMain();
List<File> list = new ArrayList<>();
final String scanPackage = "com/an/classloadertest";
Enumeration<URL> urlEnumeration = testMain.getClass().getClassLoader().getResources(scanPackage);
while (urlEnumeration.hasMoreElements()){
URL url = urlEnumeration.nextElement();
File file = new File(url.getFile());
list.add(file);
}
String[] resources = list.stream().findFirst().get().list();
for (String resource : resources){
if (resource.equals("TestMain.class")){
Class<?> testClass = Class.forName(scanPackage.replace("/", ".") + "." + resource.replace(".class", ""));
Object newInstance = testClass.newInstance();
System.out.println(newInstance); // TestMain{name='null', job='null'}
}
}
}
private static void classLoaderTest1() {
TestMain testMain = new TestMain();
System.out.println(testMain.getClass().getClassLoader().getResource(""));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/
System.out.println(testMain.getClass().getClassLoader().getResource("1.properties"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/1.properties
System.out.println(testMain.getClass().getClassLoader().getResource("com/an/classloadertest/2.properties"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/com/an/classloadertest/2.properties
System.out.println(testMain.getClass().getClassLoader().getResource("com/an/classloadertest/sub/3.properties"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/com/an/classloadertest/sub/3.properties
}
private static void classLoaderTest() {
TestMain testMain = new TestMain();
System.out.println(testMain.getClass());
//class com.an.classloadertest.TestMain
System.out.println(testMain.getClass().getClassLoader());
//sun.misc.Launcher$AppClassLoader@18b4aac2
System.out.println(testMain.getClass().getClassLoader().getResource(""));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/
System.out.println(testMain.getClass().getClassLoader().getResource("/"));
//null
}
private static void classTest() {
System.out.println(TestMain.class.getResource(""));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/com/an/classloadertest/
System.out.println(TestMain.class.getResource("/"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/
System.out.println(TestMain.class.getResource("2.properties"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/com/an/classloadertest/2.properties
System.out.println(TestMain.class.getResource("sub/3.properties"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/com/an/classloadertest/sub/3.properties
System.out.println(TestMain.class.getResource("/1.properties"));
//file:/Users/an/IdeaProjects/demo/javase/target/classes/1.properties
}
private static void test() {
System.out.println(TestMain.class.getResource(""));
// file:/Users/an/IdeaProjects/demo/javase/target/classes/com/an/classloadertest/
System.out.println(TestMain.class.getResource("/"));
// file:/Users/an/IdeaProjects/demo/javase/target/classes/
}
}
