corejava学习8(io)

 

Vector     的方法都是synchronized的

 

Arraylist   快   不安全

I/O

 

输入/输出    方向

 

字节/字符    单位

 

FileInputStream    读文件

 

Read（）返回及一个整数，表示的你读出的字节的值，

当读了返回－1

 

Read（int b［］）读满一个字节数组

fileOutputStream    写文件

 

 

 

 

import java.io.*;

public class TestOutputStream {

    public static void main(String[] args){

           OutputStream os=null;

           try {

                  os=new FileOutputStream("2.txt");

                  String str="Hello Kettas";

                  byte[] bs=str.getBytes();//将字符串数组转换成字节数组

                  os.write(bs);

           } catch (FileNotFoundException e) {

                  e.printStackTrace();

           } catch (IOException e) {

                  e.printStackTrace();

           }finally{

                  try {

                         if (os!=null) os.close();

                  } catch (IOException e) {

                         e.printStackTrace();

                  }

           }

    }

}

 

 

import java.io.*;

public class TestListFiles {

    public static void main(String[] args) {

           File dir=new File("D:\\0804corejava");

           print(dir);

    }

    static void print(File dir){

           File[] fs=dir.listFiles();

           for(int i=0;i<fs.length;i++){

                  if (fs[i].isFile()) //判断是否是一个文件

                         System.out.println(fs[i].getAbsolutePath());

                  else print(fs[i]);

           }

    }

}

 

 

 

import java.io.*;

public class TestPipedStream {

    public static void main(String[] args) throws Exception{

           PipedInputStream fis=new PipedInputStream();

           PipedOutputStream fos=new PipedOutputStream();

           fis.connect(fos);//连接

          

           Thread t=new ThreadA(fos);

           t.start();

          

           System.out.println(fis.read());

          

           fis.close();

    }

}

class ThreadA extends Thread{

    PipedOutputStream pos;

    public ThreadA(PipedOutputStream pos) {

           super();

           this.pos = pos;

    }

 

    public void run(){

           int result=0;

           try {

                  for(int i=1;i<=10;i++){

                         result+=i;

                         Thread.sleep(500);

                  }

                  pos.write(result);

                  pos.close();

           } catch (InterruptedException e) {

                  e.printStackTrace();

           } catch (IOException e) {

                  e.printStackTrace();

           }

          

    }

}

 

 

import java.io.*;

public class TestDataStream {

    public static void main(String[] args) throws Exception{

           long l=1234567890123456L;

           FileOutputStream fos=new FileOutputStream("1.dat");

           DataOutputStream out=new DataOutputStream(fos);

           out.writeLong(l);

           out.close();

          

           FileInputStream fis=new FileInputStream("1.dat");

           DataInputStream in=new DataInputStream(fis);

           long l2=in.readLong();

           in.close();关闭外层就可以

          

           System.out.println(l2);

    }

 

}

 

 

import java.io.*;

public class TestBufferedStream {

    public static void main(String[] args) throws Exception{

           String str="Hello Kettas";

           byte[] bs=str.getBytes();

           FileOutputStream fos=new FileOutputStream("kettas.txt");

           BufferedOutputStream out=new BufferedOutputStream(fos);

           //DataOutputStream dout=new DataOutputStream(out);

           out.write(bs);

           out.flush();//刷新输出流

    }

}

 

 

 

原子操作   synchronzined

 

 

ObjectOutputStream   能读八种基本的数据，带在缓冲。

序列化必须，Serializable

 

Transient   修辞的属性是临时属性，不参加序列化。

 

 

import java.io.*;

public class TestObjectStream {

    public static void main(String[] args) throws Exception{

           Student s1=new Student("Liucy",30,80);

           Student s2=new Student("Huxz",18,100);

          

           FileOutputStream fos=new FileOutputStream("students.dat");

           ObjectOutputStream out=new ObjectOutputStream(fos);

           out.writeObject(s1);

           out.writeObject(s2);

           out.close();

          

           FileInputStream fis=new FileInputStream("students.dat");

           ObjectInputStream in=new ObjectInputStream(fis);

           Object o1=in.readObject();

           Object o2=in.readObject();

           in.close();

          

           System.out.println(o1);

           System.out.println(o2);

    }

}

实现Serializable,序列化

class Student implements Serializable{

    String name;

    int age;

    transient double score;//临时属性

    public Student(String name, int age, double score) {

           super();

           this.name = name;

           this.age = age;

           this.score = score;

    }

    public String toString(){

           return "Student name="+name+" age="+age+" score="+score;

    }

}

 

 

import java.io.*;

import java.util.*;

public class TestPoemInverse {

    public static void main(String[] args) throws Exception{

           Stack s=new Stack();

          

           FileInputStream fis=new FileInputStream("1.txt");

           InputStreamReader ir=new InputStreamReader(fis);// 创建一个使用默认字符集的InputStreamReader

           BufferedReader in=new BufferedReader(ir);

           String str;

     //readLine()读取一个文本行。

           while((str=in.readLine())!=null){

                  s.push(str);

           }

           in.close();

          

           FileOutputStream fos=new FileOutputStream("2.txt");

           PrintWriter out=new PrintWriter(fos);

           int size=s.size();

           for(int i=0;i<size;i++){

                  str=s.pop();

                  out.println(str);

           }

           out.close();

          

    }

}

class Stack {

    private LinkedList list=new LinkedList();

    public void push(String str){

           list.addFirst(str);

    }

    public String pop(){

           return (String)list.removeFirst();

    }

    public int size(){

           return list.size();

    }

}

 

 

import java.io.*;

public class TestReaderWriter {

    public static void main(String[] args) throws Exception{

           FileOutputStream fos=new FileOutputStream("poem.txt");

           //Writer ow=new OutputStreamWriter(fos,"GBK");

           //PrintWriter out=new PrintWriter(ow);

           PrintWriter out=new PrintWriter(fos);

           out.println("葡萄美酒夜光杯");

           out.println("欲饮琵琶马上催");

           out.println("醉卧沙场君莫笑");

           out.println("我是流氓我怕谁");

           out.close();          

          

           FileInputStream fis=new FileInputStream("poem.txt");

           Reader ir=new InputStreamReader(fis,"Big5");

           BufferedReader in=new BufferedReader(ir);

           String str;

           while((str=in.readLine())!=null){

                  System.out.println(str);

           }

           in.close();

          

    }

}

 

 

public class TestString {

    public static void main(String[] args) throws Exception{

           String str="1232131 ";

           byte[] bs1=str.getBytes("GBK");//编码

           String str2=new String(bs1,"Big5");//解码

           System.out.println(str);

           System.out.println(str2);

          

           byte[] bs2=str2.getBytes("Big5");

           String str3=new String(bs2,"GBK");

           System.out.println(str3);

<