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‎codes/java8demo/java8demo.iml

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<?xml version="1.0" encoding="UTF-8"?>
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<module type="JAVA_MODULE" version="4" />

‎codes/java8demo/pom.xml

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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>org.example</groupId>
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<artifactId>java8demo</artifactId>
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<version>1.0-SNAPSHOT</version>
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</project>

‎codes/java8demo/src/main/java/Demo.java

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class Demo {
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public static void main(String[] args) {
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StringBuilder sb = new StringBuilder();
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for (int i = 1; i < 10; i++) {
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String chenmo = "沉默";
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String wanger = "王二";
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sb.append(chenmo);
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sb.append(wanger);
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}
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System.out.println(sb);
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s39/ReflectionDemo1.java

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package com.itwanger.s39;
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import sun.reflect.CallerSensitive;
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import sun.reflect.MethodAccessor;
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import sun.reflect.Reflection;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class ReflectionDemo1 {
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public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
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Writer writer = new Writer();
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writer.setName("沉默王二");
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System.out.println(writer.getName());
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Class clazz = Class.forName("com.itwanger.s39.Writer");
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Constructor constructor = clazz.getConstructor();
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Object object = constructor.newInstance();
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// Method setNameMethod = clazz.getMethod("setName", String.class);
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// setNameMethod.invoke(object, "沉默王二");
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// Method getNameMethod = clazz.getMethod("getName");
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// System.out.println(getNameMethod.invoke(object));
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Method setAgeMethod = clazz.getMethod("setAge", int.class);
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for (int i = 0;i < 20; i++) {
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setAgeMethod.invoke(object, 18);
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}
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s39/ReflectionDemo2.java

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package com.itwanger.s39;
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import java.lang.reflect.Method;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class ReflectionDemo2 {
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public static void target(int i) {
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new Exception("#" + i).printStackTrace();
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}
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public static void main(String[] args) throws Exception {
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Class<?> klass = Class.forName("com.itwanger.s39.ReflectionDemo2");
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Method method = klass.getMethod("target", int.class);
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for (int i = 0; i < 20; i++) {
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method.invoke(null, i);
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}
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s39/ReflectionDemo3.java

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package com.itwanger.s39;
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import java.io.PrintStream;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class ReflectionDemo3 {
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public static void main(String[] args) throws ClassNotFoundException, IllegalAccessException, InstantiationException, NoSuchMethodException, InvocationTargetException {
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//Class c1 = Class.forName("com.itwanger.s39.ReflectionDemo3");
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//System.out.println(c1.getCanonicalName());
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//
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//Class c2 = Class.forName("[D");
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//System.out.println(c2.getCanonicalName());
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//
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//Class c3 = Class.forName("[[Ljava.lang.String;");
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//System.out.println(c3.getCanonicalName());
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//Class c1 = ReflectionDemo3.class;
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//System.out.println(c1.getCanonicalName());
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//
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//Class c2 = String.class;
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//System.out.println(c2.getCanonicalName());
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//
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//Class c3 = int[][][].class;
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//System.out.println(c3.getCanonicalName());
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Class c1 = Writer.class;
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Writer writer = (Writer) c1.newInstance();
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Class c2 = Class.forName("com.itwanger.s39.Writer");
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Constructor constructor = c2.getConstructor();
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Object object = constructor.newInstance();
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Constructor[] constructors1 = String.class.getDeclaredConstructors();
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for (Constructor c : constructors1) {
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System.out.println(c);
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}
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Method[] methods1 = System.class.getDeclaredMethods();
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for (Method m : methods1) {
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System.out.println(m);
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}
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Method[] methods2 = System.class.getMethods();
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for (Method m : methods2) {
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System.out.println(m);
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}
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s39/Writer.java

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package com.itwanger.s39;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class Writer {
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private int age;
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private String name;
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public int getAge() {
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return age;
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}
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public void setAge(int age) {
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this.age = age;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s41/Demo.java

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package com.itwanger.s41;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class Demo {
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public static void main(String[] args) {
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System.out.println(10/0);
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s41/Demo1.java

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package com.itwanger.s41;
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import java.io.File;
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import java.io.IOException;
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import java.net.Socket;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class Demo1 {
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public static void main(String[] args) throws ClassNotFoundException {
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Class clz = Class.forName("com.itwanger.s41.Demo1");
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String serverName = args[0];
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int port = Integer.parseInt(args[1]);
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try {
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Socket client = new Socket(serverName, port);
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} catch (IOException e) {
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}
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s41/Demo2.java

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package com.itwanger.s41;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.net.Socket;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class Demo2 {
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private String mHost;
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private int mPort;
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private Socket mSocket;
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private final Object mLock = new Object();
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public void run() {
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if (mSocket == null) {
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initSocket();
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}
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try {
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OutputStream out = mSocket.getOutputStream();
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byte[] buffer = new byte[1024];
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int n;
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while ((n = System.in.read(buffer)) > 0) {
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out.write(buffer, 0, n);
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}
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} catch (IOException e) {
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e.printStackTrace();
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initSocket();
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}
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}
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private void initSocket() {
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while (true) {
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try {
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Socket socket = new Socket(mHost, mPort);
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synchronized (mLock) {
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mSocket = socket;
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}
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break;
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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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}

‎codes/java8demo/src/main/java/com/itwanger/s42/Demo1.java

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package com.itwanger.s42;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class Demo1 {
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static int num = 1000000;
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public static void main(String[] args) {
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// tryFun();
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// fun();
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test1();test2();
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}
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static void tryFun() {
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int sum = 0;
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long t1 = System.currentTimeMillis();
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for(int i=0;i<num;i++) {
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try {
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sum = sum + 1;
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System.out.println(sum);
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} catch (Exception e) {
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}
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}
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long t2 = System.currentTimeMillis();
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System.out.println("有 try catch 的时间：" + (t2-t1));
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}
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static void fun() {
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int sum = 0;
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long t1 = System.currentTimeMillis();
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try {
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for(int i=0;i<num;i++) {
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sum = sum + 1;
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System.out.println(sum);
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}
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} catch (Exception e) {
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}
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long t2 = System.currentTimeMillis();
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System.out.println("无 try catch 的时间：" + (t2-t1));
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}
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static void test() {
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int num1, num2;
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try {
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num1 = 0;
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num2 = 62 / num1;
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System.out.println(num2);
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System.out.println("try 块的最后一句");
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}
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catch (ArithmeticException e) {
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// 算术运算发生时跳转到这里
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System.out.println("除数不能为零");
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}
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catch (Exception e) {
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// 通用型的异常意味着可以捕获所有的异常，它应该放在最后面，
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System.out.println("异常发生了");
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}
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System.out.println("try-catch 之外的代码.");
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}
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static void test1 () {
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try{
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int arr[]=new int[7];
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arr[9]=30/1;
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System.out.println("try 块的最后");
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} catch(ArithmeticException | ArrayIndexOutOfBoundsException e){
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System.out.println("除数必须是 0");
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}
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finally {
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}
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System.out.println("try-catch 之外");
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}
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static int test2 () {
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try {
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System.exit(1);
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return 112;
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}
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finally {
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System.out.println("finally 块");
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}
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s43/ThrowDemo.java

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package com.itwanger.s43;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class ThrowDemo {
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static void checkEligibilty(int stuage){
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if(stuage<18) {
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throw new ArithmeticException("年纪未满 18 岁，禁止观影");
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} else {
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System.out.println("请认真观影!!");
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}
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}
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public static void main(String args[]){
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// checkEligibilty(10);
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// System.out.println("愉快地周末..");
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try {
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myMethod1();
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} catch (ArithmeticException e) {
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// 算术异常
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} catch (NullPointerException e) {
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// 空指针异常
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}
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}
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public static void myMethod1() throws ArithmeticException, NullPointerException{
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// 方法签名上声明异常
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}
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public void myMethod() {
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try {
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// 可能抛出异常
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} catch (ArithmeticException e) {
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// 算术异常
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} catch (NullPointerException e) {
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// 空指针异常
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}
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}
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}

‎codes/java8demo/src/main/java/com/itwanger/s45/Demo.java

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package com.itwanger.s45;
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/**
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* @author 微信搜「沉默王二」，回复关键字 Java
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*/
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public class Demo {
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public static void main(String[] args) {
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Runtime runtime = Runtime.getRuntime();
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}
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}

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