JavaSE 第二次学习随笔(五)

 public synchronized void load(Reader reader);
 public synchronized void load(InputStream inStream);
 
 public void store(Writer writer, String comments);
 public void store(OutputStream out, String comments);

//创建三个输入流
	FileInputStream fileInputStream1 = new FileInputStream("src\\com\\qianfeng\\test\\Demo2.java");
	FileInputStream fileInputStream2 = new FileInputStream("src\\com\\qianfeng\\test\\Demo2.java");
	FileInputStream fileInputStream3 = new FileInputStream("src\\com\\qianfeng\\test\\Demo1.java");
	//将三个输入流放入序列流
	------------------------------------------------------------------------
	//方式一:先放入一个Vector
	Vector<FileInputStream> vector = new Vector<>();
	vector.add(fileInputStream1);
	vector.add(fileInputStream2);
	vector.add(fileInputStream3);
	
	//得到枚举器
	Enumeration<FileInputStream> e = vector.elements();
	-------------------------------------------------------------------------

	//方式二:先放入一个list
	ArrayList<FileInputStream> list = new ArrayList<>();
	list.add(fileInputStream1);
	list.add(fileInputStream2);
	list.add(fileInputStream3);

	//将集合转换成枚举
	Enumeration<FileInputStream> e = Collections.enumeration(list);
	-------------------------------------------------------------------------

	SequenceInputStream sequenceInputStream = new SequenceInputStream(e);
	FileOutputStream fileOutputStream = new FileOutputStream("filepath");
	byte[] arr = new byte[1024];
	int num;
	while ((num = sequenceInputStream.read(arr)) != -1) {
		fileOutputStream.write(arr, 0, num);
		fileOutputStream.flush();
	}

	sequenceInputStream.close();
	fileOutputStream.close();

DataOutputStream dataOutputStream = new DataOutputStream(new FileOutputStream("filepath"));
	//写
	dataOutputStream.writeInt(97);//4个字节
	dataOutputStream.writeBoolean(true);//1个
	dataOutputStream.write(33);//1个
	dataOutputStream.writeDouble(34.56);//8个
	//关闭流
	dataOutputStream.close();
	
	//读
	DataInputStream dataInputStream = new DataInputStream(new FileInputStream("filepath"));
	dataInputStream.readBoolean();
	dataInputStream.readInt();
	dataInputStream.readByte();
	dataInputStream.readDouble();
	dataInputStream.close();

//创建输入流,关联一个byte型的数组,作为缓冲区数据
	ByteArrayInputStream bais = new ByteArrayInputStream("hello world".getBytes());

	//创建输出流-不需要指定参数
	ByteArrayOutputStream baos = new ByteArrayOutputStream();
	byte[] arr = new byte[1024];
	int num;
	while ((num = bais.read(arr)) != -1) {
		baos.write(arr, 0, num);
	}
	
	System.out.println(new String(arr));
	
	bais.close();
	baos.close();
	
	//注意:将流关闭了之后,还可以调用方法,不会报错.
	baos.write(45);

//写出--序列化
	//创建序列化流并关联文件
	ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("filepath"));
	//调用方法实现序列化
	//序列化后的内容不能直接查看,要想查看进行反序列化
	objectOutputStream.writeObject(obj);
	objectOutputStream.close();
	
	----------------------------------------------------------------------------------------------------
	
	
	//读入--反序列化
	ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("filepath"));
	//实现反序列化
	Object object = objectInputStream.readObject();

	//向下转型
	/*
	 * ClassNotFoundException:当前的类没有找到
	 * 分析:将Person对象进行序列化之后,将Person类删除,再进行反序列化的时候出现了异常
	 * 原因:反序列化在执行的时候依赖字节码文件,当类没有了,字节码文件无法创建,反序列化失败
	 */
	System.out.println(object);
	objectInputStream.close();

//获取自己的主机
InetAddress inetAddress = InetAddress.getLocalHost();
inetAddress.getHostName();	//HostName
inetAddress.getHostAddress();	//URI
//获取网络上任意一台主机
InetAddress inetAddress2 = InetAddress.getByName("www.baidu.com");//根据域名 IP地址也可以

//发送端
//* 1.创建UDP通信的对象-socket对象:对应的类是DatagramSocket.(用于UDP数据的发送与接收)
DatagramSocket datagramSocket = new DatagramSocket();
//* 2.数据的准备-封装包:DatagramPacket(数据包,包括相关的属性,数据, 数据包像快递一样, 需要地址自己发送...)
public DatagramPacket(byte buf[], int offset, int length, SocketAddress address);
public DatagramPacket(byte buf[], int length, InetAddress address, int port);
public DatagramPacket(byte buf[], int length, SocketAddress address);
//* 3.发送数据, 通过send方法
datagramSocket.send(datagramPacket);
//* 4.关闭socket对象
datagramSocket.close();

//侦听某个UDP端口
DatagramSocket datagramSocket = new  DatagramSocket(port);
// (因为是收数据包, 不需要指定自己的地址, 只需要接收就完事了)
// 将数据读入到buf中, 使用getBytes()可以获取到buf数据
public DatagramPacket(byte buf[], int length);
public DatagramPacket(byte buf[], int offset, int length);
//调用receive(DatagramPacket)将数据从网络流接收到 packet 的 buf 数组中; receive是一个阻塞方法! 可以使用socket.setSoTimeout(ms);设置阻塞超时时间,超过时间未接收到视为数据丢失
datagramSocket.receive(packet);
packet.getData();	//byte[] 获取buf数组

客户端
//1.创建Socket对象并绑定服务器的地址和端口
Socket socket = new Socket(InetAddress:InetAddress.getLocalHost(), port:22000);
//2.准备数据
String data = "BigData1712,你好";
//3.获取socket内部的输出流
OutputStream outputStream = socket.getOutputStream();
//4.将数据写入网络IO
outputStream.write(data.getBytes());
//接收从服务器传回的数据
InputStream inputStream = socket.getInputStream();
byte[] arr = new byte[1023];
int num = inputStream.read(arr);
//5.关闭资源
socket.close();


服务端

//1.创建ServerSocket对象并绑定接口
ServerSocket serverSocket  = new ServerSocket(port:22000);
//2.接收套接字的连接,保证客户端与服务器端使用同一个socket对象---对端口一直监听
Socket socket = serverSocket.accept();
//3.获取输入流
InputStream inputStream = socket.getInputStream();
//4.将内容写到控制台
byte[] arr = new byte[1023];
int num = inputStream.read(arr);
System.out.println(new String(arr,0,num));
//实现将服务器的数据写回客户端
OutputStream outputStream = socket.getOutputStream();
outputStream.write("你好,BigData1712".getBytes());
//5.关闭资源
serverSocket.close();

/**
 * 反射
 * 动态获取类的.class文件
 * 并对其成员进行抽象
 * 整体: 通过字节码文件直接创建对象
 */
//以下仅仅是对Java反射的基础概念,和基本方法的运用
Class cc = Class.forName("java.lang.Integer");
//获取全部的变量(无视权限)
Field[] fields = cc.getDeclaredFields();
//获取全部的方法(无视权限)
Method[] ms = cc.getDeclaredMethods();
//获取构造函数~ int.class是该方法的参数类型的class对象
Constructor constructor = cc.getConstructor(int.class);
//对Constructor 或Method 或 Field 的权限的修改改为setAccessible(true)
constructor.setAccessible(true);
//对获得的方法的调用
Object integer = constructor.newInstance(1010);
Method m = cc.getMethod("valueOf", int.class);
m = cc.getMethod("intValue");
System.out.println(m.invoke(integer));
//对获得的变量的调用
Field value = cc.getDeclaredField("value");
value.setAccessible(true);
System.out.println(value.get(integer));