JAVA IO流的常用类

1、简单的文件读写（FileInputStream ,FileOutputStream ）
public class testFile {
	public static void main(String[] args) throws Exception {
		/////////////////////FileInputStream/////////////////////
		// 注意String(b,0,temp)的代码// 当最后一次时会少,回车(2个字节)的读写
		FileInputStream fis = new FileInputStream("C:\\abc.txt");
		byte[] b = new byte[20];
		String re = "";
		while (true) {
			int temp = fis.read(b);
			if (temp == -1)break;				
			re = re + new String(b, 0, temp);		
		}
		fis.close();
		System.out.println(re);
		/////////////////////FileOutputStream/////////////////////
		FileOutputStream fos = new FileOutputStream("C:\\bc.txt");
		fos.write("rensongxin".getBytes());
		fos.close();
	}
}
2、文件逐行读写（BufferedReader ）
public class TestLine {
	public static void main(String[] args) throws Exception{
		FileInputStream fi=new FileInputStream("c:\\abc.txt");
		InputStreamReader ir =new InputStreamReader(fi);
		BufferedReader br = new BufferedReader(ir);
		int i=1;
		while (true){
			String temp= br.readLine();
			if(temp==null)break;
			System.out.println(i+":"+temp);
			i++;
		}
		br.close();
	}
}
3、(DataOutputStream ,DataInputStream )
public class TestData {
	public static void main(String[] args) {
		try {
			FileOutputStream fos = new FileOutputStream("c:\\test.txt");
			DataOutputStream dos = new DataOutputStream(fos);
			dos.writeInt(12345);
			dos.close();
			FileInputStream fis = new FileInputStream("c:\\test.txt");
			DataInputStream dis = new DataInputStream(fis);
			System.out.println(dis.readInt());
			dis.close();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
		}// finally
	}
}
4从键盘读一行
public class TestKey {
	public static void main(String[] args)throws Exception{
		InputStreamReader isr=new InputStreamReader(System.in);
		BufferedReader br=new BufferedReader(isr);				
			while(true){			
				String temp=br.readLine();
				if(temp.equals("bye"))break;
				System.out.println(temp);
			}
			br.close();			
		}//main
	}
5、重要**Properties 结合FileInputStream ，FileOutputStream 的使用
public class TestProperty {
	public static void main(String[] args) throws Exception{
		Properties p=new Properties();
		FileInputStream fis=new FileInputStream("c:\\db.properties");
		p.load(fis);//
		fis.close();
		String name=p.getProperty("username");
		//name = new String(name.getBytes("ISO8859-1"),"GBK");//不加 会显示乱码,当username=任松鑫时
		System.out.println(name);
		String db=p.getProperty("db");
		System.out.println(db);
		p.setProperty("year", "5");
		FileOutputStream fos=new FileOutputStream("c:\\db.properties");
		p.store(fos, "test");//
		fos.close();
	}
}
///////////////////////////
/**
文件内容
server=192.168.0.23
db=oracle
port=1521
username=zhang
password=superman
#server=192.168.0.20
#db=db2
#port=152
#username=db2
#password=ibm

c:\\db.properties
 */
6、PipedOutputStream ，PipedInputStream 的使用
public class SendThread extends Thread{
	private PipedOutputStream pos;
	public SendThread(PipedOutputStream pos){
		this.pos=pos;
	}
	public void run(){
		DataOutputStream dos=new DataOutputStream(pos);
		try{
			for(int i=0;i<10;i++){
				dos.writeInt(i*10);				
			}
			dos.close();
		}catch(Exception e){}		
	}
}

public class ReThread extends Thread{
	private PipedInputStream pis;
	public ReThread(PipedInputStream pis){
		this.pis=pis;
	}
	public void run(){
		DataInputStream dis=new DataInputStream(pis);
		try{
			for(int i=0;i<10;i++){				
				System.out.println(dis.readInt());			
			}
			dis.close();
		}catch(Exception e){}		
	}	
	public static void main(String []args)throws Exception{
		PipedInputStream pis=new PipedInputStream();
		PipedOutputStream pos=new PipedOutputStream(pis);
		new ReThread(pis).start();
		new SendThread(pos).start();
	}
}
7、File 的使用
public class TestFile {
	public static void main(String[] args) throws Exception{
		File f1 = new File("c:/a/b");
		if(!f1.exists()){
			f1.mkdirs();
			System.out.println("MKDIR");
		}
		File.createTempFile("abc",".txt",f1);
		///////////////////////////////
		String[] str = f1.list();
		for(int i=0;i<str.length;i++){
			System.out.println(str[i]);
		}
		//把f1下边的所有的子文件列出来（不要目录）
		//////////////////////////////
		File[] f = f1.listFiles();
		for(int i = 0;i<f.length;i++){
			if(f[i].isFile()){
				System.out.println(f[i].getName());
				System.out.println(f[i].getPath());
				System.out.println(f[i].getParent());
				System.out.println("*******");
			}
		}
		File ff = new File("./");
		String[] aa = ff.list();
		for(int i=0;i<aa.length;i++){
			System.out.println(aa[i]);
		}
		File file = new File("../../abc.txt");
		System.out.println(file.exists());
		//由于windows有不同的根目录，所以相对路径无法切换盘符
	}
}
8、FilenameFilter文件的过滤
public class TestFilter {
	public static void main(String[] args) throws Exception {
		// /////////文件的过滤////////////////////
		File f1 = new File("c:/a/b");
		String[] st = f1.list(new FilenameFilter() {
			public boolean accept(File f, String n) {
				return n.endsWith(".txt") || n.endsWith(".java");
			}
		});
		for (int i = 0; i < st.length; i++) {
			System.out.println(st[i]);
		}
	}
}
9、对象的序列化(ObjectOutputStream ，ObjectInputStream ,Serializable,关键字transient)
public class WritePerson {
	public static void main(String[] args) throws Exception{
		FileOutputStream fos = new FileOutputStream("c:\\person.txt");
		ObjectOutputStream oos=new ObjectOutputStream(fos);
		Person p=new Person();
		p.setAge(23);p.setName("zhang");
		p.setSex("man");
		oos.writeObject(p);
		oos.close();
	}
}

class Person implements Serializable{
	private int age;
	private String  name;
	private Object test;
	private String sex;
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Object getTest() {
		return test;
	}
	public void setTest(Object test) {
		this.test = test;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
}
public class ReadPerson {
	public static void main(String[] args) throws Exception{
		FileInputStream fis = new FileInputStream("c:\\person.txt");
		ObjectInputStream ois=new ObjectInputStream(fis);
		//对象序列化实现对象深克隆
		Person p=(Person)ois.readObject();
		ois.close();
		System.out.println(p.getName()+p.getAge());
	}
}
10、nio流（容量，界限，位置的测试）
public class NioTestBuffer {
	public static void main(String[] args) {
		CharBuffer cb=CharBuffer.allocate(8);
		cb.limit(7);
		System.out.println("before"+cb.capacity()+cb.position()+cb.limit());
		cb.put('a');cb.put('b');cb.put('c');
		System.out.println("after"+cb.capacity()+cb.position()+cb.limit());
		cb.flip();
		System.out.println("flip"+cb.capacity()+cb.position()+cb.limit());
		System.out.println(cb.get());
		System.out.println(cb.get(2));
		System.out.println("get"+cb.capacity()+cb.position()+cb.limit());
		cb.clear();
		System.out.println("clear"+cb.capacity()+cb.position()+cb.limit());
		System.out.println(cb.get(1));
	}
}
11、通道的使用FileChannel 
public class TestChannel {
//利用通道文件的快速拷贝
	public static void main(String[] args) throws Exception{
		FileInputStream fis=new FileInputStream("c:\\abc.txt");
		FileOutputStream fos=new FileOutputStream("c:\\go.txt");
		FileChannel fc1=fis.getChannel();
		FileChannel fc2=fos.getChannel();
		ByteBuffer bb=ByteBuffer.allocate(20);
		while(true){
			int temp=fc1.read(bb);
			bb.flip();//注意理解 位置回零
			if(temp==-1)break;
			fc2.write(bb);
			bb.clear();//注意理解 位置回零 界限回容量
		}
		fc1.close();
		fc2.close();
		fis.close();
		fos.close();
	}
}
12、建立直接缓冲
public class TestDirect {
	public static void main(String[] args) {
		// 建立直接缓冲
		ByteBuffer bb = ByteBuffer.allocateDirect(16);
		CharBuffer cb = bb.asCharBuffer();// CharBuffer等其他6个直接缓冲
		IntBuffer ib = bb.asIntBuffer();// 都由ByteBuffer来建立
		System.out.println(bb.capacity());
		System.out.println(cb.capacity());
		System.out.println(ib.capacity());
	}
}
13、FileChannel 的transferFrom
public class TestTransfer {
	public static void main(String[] args) throws Exception {
		FileInputStream fis = new FileInputStream("c:\\abc.txt");
		FileOutputStream fos = new FileOutputStream("c:\\go.txt");
		FileChannel fc1 = fis.getChannel();
		FileChannel fc2 = fos.getChannel();
		fc2.transferFrom(fc1, 0, fc1.size());
		// fc1.transferTo(position, count, target);
		// 注意 fc1 fc2 选一个就可以 但注意参数
		fc1.close();
		fc2.close();
		fis.close();
		fos.close();
	}
}