Java核心技术精讲-优快云博客

package com.test.java;

import org.apache.commons.io.FileUtils;
import org.junit.Test;

import java.io.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.*;
import java.text.SimpleDateFormat;
import java.util.*;

public class Day03 {

    /**
     * 一、文件File
     * 1. creatNewFile:
     * - 仅用于创建文件，而且文件所在根目录必须是存在的，不然会报错
     * - 如果文件已经存在，则返回false。不会创建新文件
     * 2. mkdir/mkdirs:
     * - mkdir创建指定的目录，但是待创建的目录前一层级目录结构必须是已经存在的，不然创建不成功
     * - 所以，建议使用mkdirs，创建全路径，不管存在不存在
     * 3. listFiles():
     * - 返回file封装路径下的所有子文件和文件夹的File对象 ，是全路径
     * - 只查找一层
     *
     * @throws IOException
     */
    @Test
    public void testFile() throws IOException {
        File file = new File("D:/Test/1.txt");
        if (file.exists()) {
            file.delete();
        }
        file.createNewFile();

//        file = new File("D:/Test/a/b/");
//        file.mkdir();
//        file.mkdirs();

        file = new File("D:/Test");
        File[] files = file.listFiles();
        for (File i : files) {
            System.out.println(i.getAbsolutePath());
        }
    }

    /**
     * 二、listFiles + 过滤器Filter
     * 1. 继承FileFilter接口，实现accept方法
     */
    @Test
    public void testFilter() {
        File file = new File("D:/Test");
        File[] files = file.listFiles(new FileFilter() {

            @Override
            public boolean accept(File pathname) {
//                System.out.println(pathname.getAbsolutePath());
                String regex = ".+\\.txt";
                return pathname.toString().matches(regex);
            }
        });
        for (File i : files) {
            System.out.println(i.getAbsolutePath());
        }
    }


    /**
     * 三、流
     * 1. InputStream 字节输入流 抽象类
     * -- FileInputStream
     * -- BufferedInputStream
     * -- DataInputStream
     * -- ObjectInputStream
     * -- StringBufferInputStream
     * -- ByteArrayInputStream
     * <p>
     * 2. OutputStream 字节输出流 抽象类
     * -- FileOutputStream
     * -- BufferedOutputStream
     * -- DataOutputStream
     * -- ObjectOutputStream
     * -- StringBufferOutputStream
     * -- ByteArrayOutputStream
     * <p>
     * 3. Reader 字符输入流
     * -- FileReader
     * -- BufferedReader
     * -- InputStreamReader
     * <p>
     * 4. Writer 字符输出流
     * -- FileWriter
     * -- BufferedWriter
     * -- OutputStreamWriter
     * <p>
     * 1.规律整理：什么时候使用什么流
     * 首先，要明确是操作字符还是字节；
     * 如果是操作字符，那么就是Reader和Writer类及其子类 FileReader和FileWriter(快捷流，使用默认编码)、OutputStreamWriter和InputStreamReader(转换流，使用自定义编码)、BufferedReader和BufferedWriter(缓冲流，使用默认编码)；最后通过具体的功能，是快捷，还是指定编码，还是高效，选择使用对应的子类流。
     * 如果是操作字节，那么就是InputStream和OutputStream类及其子类 FileInputStream和FileOutputStream（普通字节流，一般作为转换流和高效字节流的构造参数）、BufferedInputStream和BufferedOutputStream（高效字节流）；最后通过具体的功能，选择普通还是高效。
     * <p>
     * 2.类整理
     * 字节流
     * 字节输入流InputStream
     * FileInputStream:普通字节输入流
     * BufferedInputStream:高效的字节输入流，构造函数需要传入字节输入流
     * 字节输出流OutputStream
     * FileOutputStream:普通的字节输出流
     * BufferedOutputStream:高效的字节输出流，构造函数需要传入字节输出流
     * <p>
     * 字符流
     * 字符输入流Reader
     * FileReader:快捷的字符输入流，使用默认编码
     * InputStreamReader:转换流，可以自定义编码
     * BufferedReader:缓冲流，高效读取，使用默认编码
     * 字符输出流Writer
     * FileWriter:快捷的字符输出流，使用默认编码
     * InputStreamWriter:转换流，可以自定义编码
     * BufferedWriter:缓冲流，高效输出，使用默认编码
     */
    @Test
    public void testIO() {
        String path = "d:/Test/1.json";
        File file = new File(path);
        StringBuilder sb = new StringBuilder();
//        FileInputStream fileInputStream = new FileInputStream(path);

        // FileInputStream
        FileInputStream fileInputStream = null;
        try {
            fileInputStream = new FileInputStream(file);
            int len = 0;
            byte[] buf = new byte[1024];
            while ((len = fileInputStream.read(buf)) != -1) {
                sb.append(new String(buf, 0, len));
            }
            System.out.println(sb);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
//
//
        // FileOutputStream
        System.out.println("--------------------------------------");
        OutputStream outputStream = null;
        try {
            outputStream = new FileOutputStream(file, true);
            outputStream.write("\r\n".getBytes());
            outputStream.write(sb.toString().getBytes());
            outputStream.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

//        // BufferedInputStream
//        FileInputStream fileInputStream = null;
//        BufferedInputStream bufferedInputStream = null;
//        try {
//            fileInputStream = new FileInputStream(file);
//            bufferedInputStream = new BufferedInputStream(fileInputStream);
////            bufferedInputStream.read()
//        } catch (FileNotFoundException e) {
//            e.printStackTrace();
//        }
//
//        // BufferedOutputStream
//        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream();
//        bufferedOutputStream.write();


//
        // FileReader
        System.out.println("--------------------------------------");
        FileReader fileReader = null;
        try {
            fileReader = new FileReader(file);
            char[] cbuf = new char[1024];
            int len = 0;
            while ((len = fileReader.read(cbuf)) != -1) {
                sb = new StringBuilder();
                sb.append(new String(cbuf, 0, len));
            }
            System.out.println(sb);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fileReader != null) {
                try {
                    fileReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
//
        // FileWriter
        System.out.println("--------------------------------------");
        FileWriter fileWriter = null;
        try {
            fileWriter = new FileWriter(file);
            fileWriter.write(sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                fileWriter.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        // BufferedReader
        System.out.println("--------------------------------------");
        BufferedReader bufferedReader = null;
        try {
            fileReader = new FileReader(file);
            bufferedReader = new BufferedReader(fileReader);
            int len = 0;
            char[] cbuf = new char[1024];
//            bufferedReader.readLine()
            while ((len = bufferedReader.read(cbuf)) != -1) {
                sb = new StringBuilder();
                sb.append(new String(cbuf, 0, len));
            }
            System.out.println(sb);
        } catch (Exception e) {
            e.printStackTrace();
        }
//
        // BufferedWriter
        System.out.println("--------------------------------------");
        BufferedWriter bufferedWriter = null;
        try {
            fileWriter = new FileWriter(file);
            bufferedWriter = new BufferedWriter(fileWriter);
            bufferedWriter.write(sb.toString());
            bufferedWriter.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (bufferedWriter != null) {
                try {
                    bufferedWriter.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        // InputStreamReader
//        InputStreamReader inputStreamReader = new InputStreamReader();
//        inputStreamReader.read()

//        // OutputStreamWriter
//        new OutputStreamWriter().write();

    }


    /**
     * 四、Properties类
     * 1. Properties是一个集合，存储键值对。实现map接口；没有泛型，键值都是字符串，可用于持久化储存数据。
     * 2. void setProperties(String key , String value);   //存入键值对，相当于put
     * String getProperties(String key);   //取出键值对，相当于get
     * Set<String> stringPropertyNames();  //用于遍历集合，得到所有键的set集合
     * load(InputStream in); :读取指定的文件，将读取到的键值对保存到properties集合中
     * load(Reader);重载
     * store(OutputStream out , commons); //将键值对永久保存到文件中，commons代表描述信息，就是注释
     * store(Writer); //重载
     */
    @Test
    public void testProp() throws Exception {
        Properties properties = new Properties();
        File file = new File("D:/Test/a.prop");
//        properties.setProperty("id","111");
//        properties.setProperty("name","ggg");
//        FileWriter fileWriter = new FileWriter(file);
//        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
//        properties.store(bufferedWriter,"nothing");
//        System.out.println(properties.getProperty("name"));
        FileReader fileReader = new FileReader(file);
        properties.load(fileReader);
        System.out.println(properties.getProperty("name"));
    }

    /**
     * 五、序列化与反序列化
     * 1. 序列化流将Java中的对象，基本数据类型，引用类型等写入到文件中，进行持久化保存
     * 反序列化流，可以将序列化保存的文件，再次读取到内存中
     * 序列化构造方法：ObjectOutputStream(OutputStream out);
     * 反序列化构造方法:ObjectInputStream(InputStream in);
     * 写方法: void writeObject(Object obj);
     * 读方法：object readObject();
     * 瞬态关键字：transient,对成员变量进行保护，防止其被序列化
     */
    @Test
    public void testSe() throws Exception {
        Person person = new Person("xoa", 17);
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream(new File("d:/Test/p.obj")));
        objectOutputStream.writeObject(person);
        objectOutputStream.flush();
        objectOutputStream.close();

        //
        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(new File("d:/Test/p.obj")));
        Person o = (Person) objectInputStream.readObject();
        System.out.println(o.toString());
    }


    /**
     * 六、 打印流
     * 打印流一共有2个：字节打印流printStream 和 字符打印流 printWriter；
     * 就是将字符输出到指定的文件，仅仅是为了方便打印和输出，不抛出io异常，但是可能会抛出其他异常
     * printStream(File / StringName / OutputStream);
     * printWriter(File / StringName / OutputStream / Writer);
     * 如果传入的是流~可以开启自刷新功能printWriter(OutputStream out,true);
     */
    @Test
    public void testPrintStream() throws Exception {
        PrintStream printStream = new PrintStream("d:/Test/1.log");
        printStream.print("xxxxx");
        printStream.println("mmmmm");
        PrintWriter printWriter = new PrintWriter("d:/Test/1.log");
        printWriter.println("vvvvv");
        printStream.close();
        printWriter.close();
    }

    /**
     * 七、数组
     */
    @Test
    public void testArray() {
        int[] array = {1, 4, 6, 2, 3, 8, 6, 7, 9};
        // 排序
        Arrays.sort(array);
        // 查找
        System.out.println(Arrays.binarySearch(array, 5));

        ArrayList<Integer> list = new ArrayList<>();
        Integer i = new Integer(3);
        list.add(1);
        list.add(i);
        list.add(6);
        list.add(2);
        list.add(4);
        // 反转
        Collections.reverse(list);
        // 查找
        Collections.sort(list);
        System.out.println(Collections.binarySearch(list, new Integer(3)));
        // 数组转List
        String[] a = {"a", "b"};
        ArrayList<String> strings = new ArrayList<>(Arrays.asList(a));
        Integer[] in = {1, 2};
        ArrayList<Integer> integers = new ArrayList<>(Arrays.asList(in));
        int[] inn = {1, 2};
        ArrayList<int[]> ints = new ArrayList<>(Arrays.asList(inn));

        // list 转数组
        Object[] objects = integers.toArray();

        // 数组填充
        array = new int[5];
        Arrays.fill(array, 50);
        Arrays.fill(array, 2, 3, 88);

        // 数组拷贝
        int[] ll = {1, 2, 3};
        array = new int[5];
        System.arraycopy(ll, 0, array, 0, 2);
        System.out.println(array);

        // 计算差集，removeAll
        boolean b = list.removeAll(list);
        System.out.println(list);

        // 计算交集
        boolean b1 = list.retainAll(list);

        // 包含
        list.contains(5);

        // 判断数组是否相等
        list.equals(list);
    }

    /**
     * 八、方法
     */
    public void testFunc() {
        EE ee = EE.aa;
        switch (ee) {
            case aa:
                break;
            case bb:
                break;
            case cc:
                break;
            case dd:
                break;
        }
    }

    /**
     * 九、目录操作
     */
    @Test
    public void testDir() {
        // 删除目录
        deleteDir(new File("D:\\Test\\out1.json"));
        // 获取目录大小
        getDirSize("D:\\HIVE_CLIENT-configs");
        // 遍历目录
        getListDir(new File("D:\\HIVE_CLIENT-configs"));
    }

    // 递归删除
    public void deleteDir(File dir) {
        if (dir.isDirectory()) {
            Arrays.asList(dir.list()).forEach(x -> {
                deleteDir(new File(dir, x));
            });
        }
        dir.delete();
    }

    // 获取目录的大小
    public void getDirSize(String path) {
        long l = FileUtils.sizeOfDirectory(new File(path));
        System.out.printf("size is %d", l);
    }

    // 遍历目录
    public void getListDir(File file) {
        System.out.println(file.getAbsolutePath());
        if (file.isDirectory()) {
            Arrays.asList(file.list()).forEach(x -> {
                getListDir(new File(file, x));
            });
        }
    }

    /**
     * 十、链表
     */
    public void testLinkedList() {
        // 删除链表元素
        LinkedList<String> strings = new LinkedList<>();
        strings.add("1");
        strings.add("2");
        strings.add("3");
        String re = strings.removeFirst();
        List<String> strings1 = strings.subList(2, 4);
        // 元素查找
        strings.indexOf("3");
        // 获取最大元素
        Collections.max(strings);
        // 修改链表
        strings.set(2, "cc");
        // 旋转链表
        Collections.swap(new ArrayList<String>(), 2, 3);
    }

    /**
     * 十一、集合
     */
    @Test
    public void testCollection() {
        // 遍历map
        HashMap<String, String> hashMap = new HashMap<>();
        hashMap.keySet().forEach(x -> {
            System.out.printf("key is %s, value is %s \r\n", x, hashMap.get(x));
        });
        Iterator<String> iterator = hashMap.keySet().iterator();
        while (iterator.hasNext()) {
            String key = iterator.next();
            String value = hashMap.get(key);
            System.out.printf("key is %s, value is %s \r\n", key, value);
        }

        // 打乱集合顺序
        Collections.shuffle(new ArrayList<>());

        // 遍历
        HashSet<String> set = new HashSet<>();
        Iterator<String> iterator1 = set.iterator();
        while (iterator1.hasNext()) {
            iterator1.next();
        }
        set.forEach(x -> {
            System.out.println(x);
        });

        // 只读集合
        List<Integer> list = Arrays.asList(new Integer[]{1, 2, 3, 4});
        List<Integer> list1 = Collections.unmodifiableList(list);
        list1.add(1);

        // 部分对调  -- dis > 0 表示第一个元素 往后挪几个位置
        //  -- dis < 0  表示最后一个元素，往前挪几个位置
        List<String> list2 = Arrays.asList("one two three four five".split("\\s+"));
        Collections.rotate(list2, -4);
        list2.forEach(x -> System.out.println(x));

        // 查找最大值最小值
        Collections.max(list2);
        Collections.min(list2);


        Hashtable table = new Hashtable<>();
        table.put("1", "one");
        table.put("2", "two");
        table.put("3", "three");
        Enumeration keys = table.keys();
        while (keys.hasMoreElements()) {
            Object o = keys.nextElement();
            System.out.println(table.get(o.toString()).toString());
        }

        // 元素替换
        List<String> list3 = Arrays.asList("1,1,2,3,3,3,3".split(","));
        Collections.replaceAll(list3, "88", "cc");
        list.forEach(x -> System.out.print(x));
        System.out.println("");

        // 查看一个列表是否在另一个列表中
        int index = Collections.indexOfSubList(list, Arrays.asList(new String[]{"3", "3"}));
        System.out.println("index is :" + index);
        int index1 = Collections.lastIndexOfSubList(list, Arrays.asList(new String[]{"3", "3"}));
        System.out.println("last index is :" + index1);
    }

    /**
     * 十二、Socket
     */
    @Test
    public void testSocket() throws Exception {
//        getHosts("www.baidu.com");
//        isPortUsed();
//        crawl("http://www.baidu.com");
//        getHeadInfo("http://www.runoob.com");
//        anylizeURL("http://www.runoob.com");a
    }

    // 获取 hosts
    public void getHosts(String url) throws Exception {
        InetAddress byName = InetAddress.getByName(url);
        String hostName = byName.getHostName();
        String hostAddress = byName.getHostAddress();
        System.out.println(hostName + "-" + hostAddress);
    }

    // 查看端口是否占用
    public void isPortUsed() {
        Socket Skt;
        String host = "localhost";
        for (int i = 0; i < 1024; i++) {
            try {
                System.out.println("查看 " + i);
                Skt = new Socket(host, i);
                System.out.println("端口 " + i + " 已被使用");
            } catch (UnknownHostException e) {
                System.out.println("Exception occured" + e);
                break;
            } catch (IOException e) {
            }
        }
    }


    // 判断主机端口
    public static boolean isSocketAliveUitlitybyCrunchify(String hostName, int port) {
        boolean isAlive = false;

        // 创建一个套接字
        SocketAddress socketAddress = new InetSocketAddress(hostName, port);
        Socket socket = new Socket();

        // 超时设置，单位毫秒
        int timeout = 2000;

        log("hostName: " + hostName + ", port: " + port);
        try {
            socket.connect(socketAddress, timeout);
            socket.close();
            isAlive = true;

        } catch (SocketTimeoutException exception) {
            System.out.println("SocketTimeoutException " + hostName + ":" + port + ". " + exception.getMessage());
        } catch (IOException exception) {
            System.out.println(
                    "IOException - Unable to connect to " + hostName + ":" + port + ". " + exception.getMessage());
        }
        return isAlive;
    }

    private static void log(String string) {
        System.out.println(string);
    }

    private static void log(boolean isAlive) {
        System.out.println("是否真正在使用: " + isAlive + "\n");
    }

    // 获取本机主机名和ip
    public void getLocalHostName() throws UnknownHostException {
        InetAddress localHost = InetAddress.getLocalHost();
        String hostName = localHost.getHostName();
        String hostAddress = localHost.getHostAddress();
    }

    // 获取远程文件的大小
    public void getRemoteFileSize() throws IOException {
        int size;
        URL url = new URL("http://www.runoob.com/wp-content/themes/runoob/assets/img/newlogo.png");
        URLConnection conn = url.openConnection();
        size = conn.getContentLength();
        if (size < 0)
            System.out.println("无法获取文件大小。");
        else
            System.out.println("文件大小为：" + size + " bytes");
        conn.getInputStream().close();
    }

    // 查看最终修改时间
    public void getLastModifiedTime() throws IOException {
        URL u = new URL("http://127.0.0.1/test/test.html");
        URLConnection uc = u.openConnection();
        SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        uc.setUseCaches(false);
        long timestamp = uc.getLastModified();
        System.out.println("test.html 文件最后修改时间 :" + ft.format(new Date(timestamp)));
    }

    // 网页抓取
    public void crawl(String path) throws IOException {
        URL url = new URL(path);
        BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
        BufferedWriter writer = new BufferedWriter(new FileWriter(new File("data.html")));
        String line = null;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
            writer.write(line);
            writer.newLine();
        }
        reader.close();
        writer.close();
    }

    // 获取URL响应头的日期
    public void getHeadDate(String path) throws IOException {
        URL url = new URL(path);
        URLConnection urlConnection = url.openConnection();
        long date = ((HttpURLConnection) urlConnection).getDate();
        System.out.printf("Data is %s\r\n", new Date(date));
    }

    // 获取URL响应头信息
    public void getHeadInfo(String path) throws IOException {
        URL url = new URL(path);
        URLConnection urlConnection = url.openConnection();
        Map<String, List<String>> fields = urlConnection.getHeaderFields();
        fields.forEach((x, y) -> {
            System.out.println(x);
            y.forEach(z -> {
                System.out.println(z);
            });
        });
    }

    // 解析URL
    public void anylizeURL(String path) throws MalformedURLException {
        URL url = new URL(path);
        System.out.println("URL 是 " + url.toString());
        System.out.println("协议是 " + url.getProtocol());
        System.out.println("文件名是 " + url.getFile());
        System.out.println("主机是 " + url.getHost());
        System.out.println("路径是 " + url.getPath());
        System.out.println("端口号是 " + url.getPort());
        System.out.println("默认端口号是 "
                + url.getDefaultPort());
    }

    // 服务端
    @Test
    public void server() throws IOException {
        ServerSocket serverSocket = new ServerSocket(8888);
        System.out.println("启动服务器");
        Socket accept = serverSocket.accept();
        InetAddress clientAddr = accept.getInetAddress();
        InetAddress localHost = clientAddr.getLocalHost();
        System.out.printf("客户端连接：%s - %s\r\n", localHost.getHostName(), localHost.getHostAddress());
        BufferedReader reader = new BufferedReader(new InputStreamReader(accept.getInputStream()));
        String msg = reader.readLine();
        System.out.println("客户端：" + msg);
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(accept.getOutputStream()));
        bw.write(msg + "\n");
        bw.flush();
    }

    // 客户端
    @Test
    public void client() throws IOException {
        Socket s = new Socket("localhost", 8888);
        //构建IO
        InputStream is = s.getInputStream();
        OutputStream os = s.getOutputStream();
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
        //向服务器端发送一条消息
        bw.write("测试客户端和服务器通信，服务器接收到消息返回到客户端\n");
        bw.flush();
        //读取服务器返回的消息
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        String mess = br.readLine();
        System.out.println("服务器：" + mess);
    }
    
    /**
     * 十三、多线程
     */
    @Test
    public void testThread() {
        Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                // 获取当前线程名称
                Thread t = Thread.currentThread();
                t.getId();
                // 获取所有线程
                t.getThreadGroup();
                // 获取线程状态
                t.getState();
                // 查看线程的优先级
                t.getPriority();
                try {
                    // 线程挂起
                    t.join();
                    // 线程终止
                    t.interrupt();
                    t.join();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("thread is" + t.getName());
            }
        });
        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("thread is" + Thread.currentThread());
            }
        });
        thread1.start();
        // 查看线程是否存活
        System.out.printf("thread is %s\r\n", thread1.isAlive());
        thread2.start();
    }

    /**
     * 十四、反射
     */
    @Test
    public void testReflect() throws Exception {
        RePerson tom = new RePerson("tom", 11);
        Class<?> rePerson = Class.forName("com.test.java.RePerson");
        // 通过反射获取实例
        RePerson o = (RePerson) rePerson.newInstance();
        o.name = "tom";
        o.age = 11;
        o.eat();
        System.out.println(o.age);
        System.out.println(o.name);

        System.out.println(rePerson.getName());
        System.out.println(tom.getClass().getName());

        System.out.println(rePerson.hashCode());
        System.out.println(RePerson.class.hashCode());

        // 通过反射获取方法
        Method func = rePerson.getDeclaredMethod("func", int.class);
        Object invoke = func.invoke(o, 5);

        // 通过反射获取指定的构造器，通过构造器获取对象
        Constructor<?> constructor = rePerson.getDeclaredConstructor(String.class, int.class);
        RePerson tomm = (RePerson) constructor.newInstance("tomm", 188);
        tomm.eat();

        // 通过发射获取字段
        Field name = rePerson.getDeclaredField("name");
        name.set(tomm, "xxxxxxxxx");
        tomm.eat();
    }

}

/**
 * 十五、多线程避免死锁
 */
class Jar {
    private Integer remain = new Integer(0);
    private final int MAX = 10;

    public void add(int i) {
        synchronized (this) {
            while (remain + i > MAX) {
                try {
                    wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            remain += i;
            System.out.printf("add %d, remain %d\r\n", i, remain);
            notify();
        }
    }

    public void cost(int i) {
        synchronized (this) {
            while (i > remain) {
                try {
                    wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            remain -= i;
            System.out.printf("cost %d, remain %d\r\n", i, remain);
            notify();
        }
    }
}

class Eat extends Thread {
    private Jar j;

    public Eat(Jar j) {
        this.j = j;
    }

    @Override
    public void run() {
        while (true) {
            try {
                Thread.sleep(1000);

            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            j.cost(2);
            System.out.println("消耗2");
        }
    }
}

class Bee extends Thread {
    private Jar j;

    public Bee(Jar j) {
        this.j = j;
    }

    @Override
    public void run() {
        while (true) {
            try {
                Thread.sleep(1000);

            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            j.add(1);
            System.out.println("add 1");
        }
    }
}

/**
 * 单例模式
 */
class Dog1 {

    private com.test.java.Dog1 instance = null;
    private final Object lock = new Object();

    private Dog1() {

    }

    public com.test.java.Dog1 getInstance() {
        if (instance == null) {
            synchronized (lock) {
                if (instance == null) {
                    instance = new com.test.java.Dog1();
                }
            }
        }
        return instance;
    }
}

enum EE {aa, bb, cc, dd}

class Person implements Serializable {
    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Person)) return false;
        Person person = (Person) o;
        return getAge() == person.getAge() &&
                getName().equals(person.getName());
    }

    @Override
    public int hashCode() {
        return Objects.hash(getName(), getAge());
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

class RePerson {
    String name;
    int age;

    public RePerson(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public RePerson() {

    }

    public void eat() {
        System.out.println(name + "==" + age);
    }

    public void func(int i) {
        System.out.println(name + "vvvvvvvvvvvvvvvvvvv" + age + "/"+ i);
    }


}
Java复习（全）
