UDP传输基本数据类型、对象、文件

接收端和发送端是两个类。

基本数据类型：

//发送端
 public static void clientData() throws Exception {
        DatagramSocket client = new DatagramSocket(8888);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(new BufferedOutputStream(baos));
        //操作数据类型+数据
        dos.writeChar(12);//int
        dos.writeUTF("nihao");//String
        dos.flush();//要刷新一下，不刷新可能会报EOFException错误
        byte[] datas = baos.toByteArray();
        DatagramPacket packet = //下面的第四个参数是创建本机的，9999要和接收端那指定的端口一致，不然会丢失数据包
                new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 9999));
        client.send(packet);
        client.close();
    }

//接收端
 public static void serverData() throws Exception {
        // Address already in use: Cannot bind 这个错误是由于同一个机子同一协议下端口冲突
        DatagramSocket server = new DatagramSocket(9999);
        byte[] container = new byte[1024*60];//最多只能操作1024*60的数据，太大会报错
        DatagramPacket packet = new DatagramPacket(container,0,container.length);
        server.receive(packet);
        byte[] datas = packet.getData();
        DataInputStream dis = new DataInputStream(new BufferedInputStream(new ByteArrayInputStream(datas)));
        //顺序与读取一致,不然会报EOFException错误
        int a = dis.readChar();
        String s = dis.readUTF();
        System.out.println(a);
        server.close();
    }

可以发现，用的就是IO流的数据流。

对象：

//来个对象
class Dog implements java.io.Serializable{
    private int age;
    private String coloer;
    //private transient String coloer; 加了transient不会被序列化

    public Dog(int age, String coloer) {
        this.age = age;
        this.coloer = coloer;
    }

    public String shout(){
        return "汪汪";
    }

    public int getAge() {
        return age;
    }

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

    public String getColoer() {
        return coloer;
    }

    public void setColoer(String coloer) {
        this.coloer = coloer;
    }
}
//发送端
 public static void clientObject() throws Exception {
        DatagramSocket client = new DatagramSocket(8888);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(new BufferedOutputStream(baos));
        //操作数据类型+数据
        oos.writeChar(12);//int
        oos.writeUTF("nihao");//String
        //对象 String,Date这两个类都实现了java.io.Serializable
        oos.writeObject("字符串对象");
        oos.writeObject(new Date());
        Dog dog = new Dog(2,"黄色");
        oos.writeObject(dog);
        oos.flush();//要刷新一下，不刷新可能会报EOFException错误
        byte[] datas = baos.toByteArray();
        DatagramPacket packet = //下面的第四个参数是创建本机的，9999要和接收端那指定的端口一致，不然会丢失数据包
                new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 9999));
        client.send(packet);
        client.close();
    }
//接收端
 public static void serverObject() throws Exception {
        // Address already in use: Cannot bind 这个错误是由于同一个机子同一协议下端口冲突
        DatagramSocket server = new DatagramSocket(9999);
        byte[] container = new byte[1024*60];//最多只能操作1024*60的数据，太大会报错
        DatagramPacket packet = new DatagramPacket(container,0,container.length);
        server.receive(packet);
        byte[] datas = packet.getData();
        ObjectInputStream ois = new ObjectInputStream(new BufferedInputStream(
                new ByteArrayInputStream(datas)));
        //顺序与读取一致,不然会报EOFException错误
        int a = ois.readChar();
        String s = ois.readUTF();
        Object str = ois.readObject();
        Object date = ois.readObject();
        Object d = ois.readObject();
        System.out.println();

        if(str instanceof String){
            String sObject = (String)str;
            System.out.println(sObject);
        }
        if(date instanceof Date){
            Date  dateObject = (Date)date;
            System.out.println(dateObject);
        }
        if(d instanceof Dog){
            Dog dogObject = (Dog) d;
            System.out.println(dogObject.getColoer()+"---"+dogObject.shout());
        }
        server.close();
    }

用的是IO流的对象流

文件、图片：

//发送端
 public static void clientFile() throws Exception {
        DatagramSocket client = new DatagramSocket(8888);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        //最多只能操作1024*60的数据，太大会报错
        byte[] datas =TestButtJoint.fileToByteArray("src/child.jpg");
        DatagramPacket packet = //下面的第四个参数是创建本机的，9999要和接收端那指定的端口一致，不然会丢失数据包
                new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 9999));
        client.send(packet);
        client.close();
    }
//接收端
 public static void serverFile() throws Exception {
        // Address already in use: Cannot bind 这个错误是由于同一个机子同一协议下端口冲突
        DatagramSocket server = new DatagramSocket(9999);
        byte[] container = new byte[1024*60];//最多只能操作1024*60的数据，太大会报错
        DatagramPacket packet = new DatagramPacket(container,0,container.length);
        server.receive(packet);
        byte[] datas = packet.getData();
        TestButtJoint.byteArrayToFile(datas,"src/child1.jpg");
        server.close();
    }

代码里的TestButtJoint是IO流的对接流，用的里面的两个方法。