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henrysworldhenrysworld
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commit my first homework
1 parent 201be61 commit a7e5990

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‎01jvm/java11/src/main/java/com/example/demo/Hello.java‎

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package com.example.demo;
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public class Hello {
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public static void main(String[] args){
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System.out.println("Hello this is my first Classload!!");
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int a = 1;
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long b = 2l;
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float c = 3.0f;
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double d = 4.0d;
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char e = 'a';
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byte f = 5;
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short g = 6;
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boolean h = true;
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int[] i = {1,2,3,4,5,6};
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int sum1 = (int) (a + b);
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int sum2 = e - a;
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int sum3 = (int) (c * d);
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int sum4 = a / f;
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System.out.println("sum1 = " + sum1);
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System.out.println("sum2 = " + sum2);
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System.out.println("sum3 = " + sum3);
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System.out.println("sum4 = " + sum4);
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if (a == b){
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System.out.println("a = b");
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}
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for (int j = 0; j < i.length; j++){
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System.out.println("for" + j + " = " + i[j]);
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}
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}
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}

‎01jvm/java11/src/main/java/com/example/demo/Hello.xlass‎

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5EA���������������������������������Ö��������֩���������𳖑�����������������������������������������ѕ������������������췚����ߜ�������������������������������Г���а���������Г���Ь�������������곕���Ж�Я�������������앞��Ж�Я�����������������������׳����Г���Ь������֩�����������������������������������H��N��������������������������������������M����I��N������������������������������

‎01jvm/java11/src/main/java/com/example/demo/HelloClassLoader.java‎

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package com.example.demo;
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import java.util.Base64;
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public class HelloClassLoader extends ClassLoader{
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public static void main(String[] args){
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try {
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new HelloClassLoader().findClass("com.example.demo.Hello").newInstance();
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} catch (InstantiationException e) {
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e.printStackTrace();
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} catch (IllegalAccessException e) {
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e.printStackTrace();
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} catch (ClassNotFoundException e) {
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e.printStackTrace();
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}
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}
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@Override
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protected Class<?> findClass(String name) throws ClassNotFoundException {
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String helloBase64 = "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";
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byte[] bytes = decode(helloBase64);
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return defineClass(name, bytes, 0, bytes.length);
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}
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public byte[] decode(String base64){
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return Base64.getDecoder().decode(base64);
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}
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}

‎01jvm/java11/src/main/java/com/example/demo/XlassLoader.java‎

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package com.example.demo;
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import java.io.Closeable;
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import java.io.IOException;
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import java.io.InputStream;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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public class XlassLoader extends ClassLoader{
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public static void main(String[] args){
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String className = "com.example.demo.Hello";
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String methodName = "hello";
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XlassLoader xlassLoader = new XlassLoader();
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try {
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Class<?> cxlazz = xlassLoader.loadClass(className);
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for (Method method : cxlazz.getMethods()){
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System.out.println(cxlazz.getSimpleName() + "." + method.getName());
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}
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Object instance = cxlazz.getDeclaredConstructor().newInstance();
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//调用实例
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Method method = cxlazz.getMethod(methodName);
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method.invoke(instance);
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} catch (ClassNotFoundException e) {
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e.printStackTrace();
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} catch (InvocationTargetException e) {
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e.printStackTrace();
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} catch (InstantiationException e) {
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e.printStackTrace();
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} catch (IllegalAccessException e) {
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e.printStackTrace();
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} catch (NoSuchMethodException e) {
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e.printStackTrace();
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}
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};
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@Override
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protected Class<?> findClass(String name) throws ClassNotFoundException {
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String resourcePath = name.replace(".", "/");
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String suffix = ".xlass";
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InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream(resourcePath + suffix);
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try {
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int length = inputStream.available();
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byte[] byteArray = new byte[length];
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inputStream.read(byteArray);
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//转换
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byte[] classBytes = decode(byteArray);
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return defineClass(name, classBytes, 0, classBytes.length);
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} catch (IOException e) {
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e.printStackTrace();
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throw new ClassNotFoundException(name, e);
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} finally {
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close(inputStream);
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}
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}
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/**
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* 解码
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* @param byteArray
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* @return
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*/
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public static byte[] decode(byte[] byteArray){
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byte[] bytes = new byte[byteArray.length];
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for (int i = 0; i < byteArray.length; i++){
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bytes[i] = (byte) (255 - byteArray[i]);
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}
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return bytes;
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}
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public static void close(Closeable res){
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if (res != null){
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try {
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res.close();
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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}
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}

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