Java I/O常用流示例

package io;
import java.io.*;
/**
* 利用缓冲区原理,BufferedInputStream,
* 实现的文件字节流读取功能示范
* @author 辉太郎
*/
public class BufferedInOutputStream {
public BufferedInOutputStream() {
   ioTest2();
}
public void ioTest2() {
   FileInputStream in = null ;
   BufferedInputStream bi = null;
   int i= 0;
   int count=0;
   try{
    in = new FileInputStream("D:/j/o/java2.txt");
    bi = new BufferedInputStream(in);
    while(( i=bi.read())!=-1) {
     System.out.print((char)i);
     count++;
    }
    System.out.println(count);
    in.close();
    bi.close();
   }catch (IOException e){
    e.printStackTrace();
   }
}
public static void main(String[] args) {

   new BufferedInOutputStream();
} 
}




package io;

import java.io.*;

/**
* 利用缓冲区原理,BufferedInputStream, 
* 实现的文件字符流读取和写入功能示范
* @author 辉太郎
*/
public class BufferedReaderWriter {
public BufferedReaderWriter() {
   bufferRdWter();
}

public void bufferRdWter() {
   FileReader fr = null;
   FileWriter wt = null;
   BufferedReader br = null;
   BufferedWriter bw = null;
   String s = "";
   try {
    fr = new FileReader("D:/j/o/java.txt");
    br = new BufferedReader(fr);
    wt = new FileWriter("D:/j/o/javat2.txt");
    bw = new BufferedWriter(wt);

    while ((s = br.readLine()) != null) {

     bw.write(s);
    }

   } catch (FileNotFoundException e) {
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   } finally {

    try {
     bw.flush();
     wt.close();
     bw.close();
     br.close();
     fr.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }
}
public static void main(String[] args) {
   new BufferedReaderWriter();
}
}




package io;

import java.io.*;

/**
* 数据流,注意的是先进先出.数据流方便我们用IO输出基本数据类型的值.比如它提供readDouble();
* @author 辉太郎
*/
public class DataInOutputStream {
public DataInOutputStream() {
   dataInOutputStream();
}

public void dataInOutputStream() {

   ByteArrayOutputStream bs = new ByteArrayOutputStream();
   DataOutputStream ds = new DataOutputStream(bs);

   try {
    ds.writeDouble(Math.random());
    ds.writeBoolean(false);

    // 其中bs.toByteArray()是把开始我们写入的东西放到这个字节数组中,然后我们从这个字节数组中取出数据
    ByteArrayInputStream bi = new ByteArrayInputStream(bs.toByteArray());
    DataInputStream di = new DataInputStream(bi);

    System.out.println(di.available());
    System.out.println(di.readDouble());
    System.out.println(di.readBoolean());

    di.close();
    bi.close();
    ds.close();
    bs.close();

   } catch (IOException e) {
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   new DataInOutputStream();

}

}




package io;

import java.io.*;

/**
*  
* FileInputStream/FileOutputStream的示例
* @author 辉太郎
*/
public class InOutputStream {
public InOutputStream() {
   inOutputStream();
}

public void inOutputStream() {
   InputStream is = null;
   OutputStream os = null;
   byte[] b;
   int i = 0;
   try {
    is = new FileInputStream("D:/j/o/java2.txt");
    os = new FileOutputStream("D:/j/o/java.txt");
    b = new byte[is.available()];
    while ((i = is.read(b)) != -1) {
     os.write(b);
    }
   
    os.close();
    is.close();

   } catch (IOException e) {
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   new InOutputStream();
}
}



package io;

import java.io.*;

/**
* 
* 转换流示例,这个流最大的作用就是将字节流转换成字符流来用!
* @author 辉太郎
*/
public class InOutputStreamReaderWriter {
public InOutputStreamReaderWriter() {
   inOutputReaderWriter();
}

public void inOutputReaderWriter() {
   InputStreamReader ir = null;
   OutputStreamWriter ow = null;
   int i = 0;
   try {
    ir = new InputStreamReader(new FileInputStream("D:/j/o/java.txt"));
    ow = new OutputStreamWriter(new FileOutputStream(
      "D:/j/o/java2.txt", true), "ISO8859-1");// latin-1
    System.out.println(ow.getEncoding());

    while ((i = ir.read()) != -1) {
     ow.write(i);
    }
    ow.write("java.io");
   } catch (IOException e) {
    e.printStackTrace();
   } finally {

    try {
     ow.flush();
     ow.close();
     ir.close();
    } catch (IOException e) {
     e.printStackTrace();
    }

   }

}

public static void main(String[] args) {
   new InOutputStreamReaderWriter();

}

}



package io;

import java.io.*;

/**
* InputStreamReader外面套一个BufferedReader,来实现接受控制台System.in输入的字符
* 
* @author 辉太郎
*/
public class InputStreamSystemIn {
public InputStreamSystemIn() {
   systemInIo();
}

public void systemInIo() {
   String s = "";
   InputStreamReader ir = null;
   BufferedReader br = null;
   ir = new InputStreamReader(System.in);
   br = new BufferedReader(ir);

   try {

    while (s != null) {
     s = br.readLine();
     if (s.equals("2")) {
      break;
     } else {
      System.out.println(s);
     }
    }
    br.close();
    ir.close();
   } catch (IOException e) {
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   new InputStreamSystemIn();
}
}



package io;

import java.io.*;

/**
* ObjectStream流,对象序列化
* @author 辉太郎
*/
public class ObjectStream {
public ObjectStream() {
   objectStream();
}

public void objectStream() {
   Test t = new Test();
   try {
    FileOutputStream fs = new FileOutputStream("D:/j/o/java.dat");
    ObjectOutputStream oo = new ObjectOutputStream(fs);
    oo.writeObject(t);

    FileInputStream fi = new FileInputStream("D:/j/o/java.dat");
    ObjectInputStream oi = new ObjectInputStream(fi);
    Test tt = (Test) oi.readObject();
    System.out.println(tt.d + " " + tt.i + " " + tt.k + " " + tt.s);

   } catch (IOException e) {

    e.printStackTrace();
   } catch (ClassNotFoundException e) {

    e.printStackTrace();
   }
}

public static void main(String[] args) {

   new ObjectStream();

}

}

class Test implements Serializable {
int i = 22;

int k = 11;

// 下面的transient关键字,作用是将d设为透明的,不存在的,然后在输出的时候就输出默认值
transient double d = 22.22;

String s = "string";
}

---------------------------------------

package io;

import java.io.*;

/**
* PrintStream 打印输出流.下面这个例子 它是通过设置System.setOut来指向我们FileOutputStream 指向的文件流
* 所以最后输出就是在这个java.txt文件里面
* 
*/
public class PrintStreamTest {
PrintStreamTest() {
   printStreamT();
}

public void printStreamT() {
   PrintStream ps = null;
   try {
    FileOutputStream fis = new FileOutputStream("D:/j/o/java.txt");
    ps = new PrintStream(fis);

    if (ps != null) {
     System.setOut(ps);
    }

    System.out.println("高枕吴忧");
   } catch (FileNotFoundException e) {
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   new PrintStreamTest();

}

}

-------------------------------------

package io;

import java.io.*;
import java.util.Date;

/**
* @author 高枕吴忧
* 利用PrintWriter实现的一个"虚假"的日志处理
*
*/
public class PrintWriterTest {

public PrintWriterTest() {
   printWriter();
}

public void printWriter() {
   String s = null;
   BufferedReader br = 
    new BufferedReader(new InputStreamReader(System.in));
   try {
    BufferedWriter bw = 
     new BufferedWriter(new FileWriter("D:/j/o/java.txt",true));
    PrintWriter log = 
     new PrintWriter(bw);
    while((s = br.readLine()) != null) {
     if(s.equalsIgnoreCase("exit")){
      break;
     }
     log.println(" - - - - - - - - - - - -");
     log.println(s.toUpperCase());
     log.flush();
    }
    log.println("===="+new Date()+"====");
    log.flush();
    log.close();
   
   } catch (IOException e) {
   
    e.printStackTrace();
   }
}


public static void main(String[] args) {
   new PrintWriterTest();

}

}

-------------------------------------

package io;

import java.io.*;

/**
* @author 高枕吴忧
* Reader/Writer字符输入输出流示例.
*
*/
public class ReaderWriter {
public ReaderWriter() {
   readerWriter();
}
public void readerWriter() {
   Reader rd = null;
   Writer wt = null;
   int i = 0 ;
   try {
    rd = new FileReader("D:/j/o/java.txt");
    wt = new FileWriter("D:/j/o/javat2.txt");
    while((i = rd.read()) != -1) {
     wt.write(i);
    }
    wt.flush();
    wt.close();
    rd.close();
   
   } catch (FileNotFoundException e) { 
    e.printStackTrace();
   } catch (IOException e) { 
    e.printStackTrace();
   }
}
public static void main(String[] args) {
   new ReaderWriter();
}

}