输入输出流

FileInputStream 读取文件中的信息，以文件作为数据来源——从文件读取的两种方式       第一种，中文字符会出现乱码   第二种，中中文不会出现乱码
        public class FileInputStreamDemo {
        　　 public static void main(String[ ] args) throws IOException {
            try{
                    FileInputStream readFile = new FileInputStream("read.txt");//这个地方的路径有相对路径和绝对路劲
                    int intTemp = readFile.read( );
                    while(intTemp!=-1){
                      System.out.print((char)intTemp);
                      intTemp = readFile.read( );
                    }
                    readFile.close( );
                    }catch(IOException ex){

                    }        
                }
                
            try
            {
                FileInputStream readFile = new FileInputStream("read.txt");
                byte[ ]  buffer = new byte[2048];
                int  byteLength = readFile.read(buffer , 0 , 2048);
                String  str = new String(buffer , 0 , byteLength);
                System.out.println(str);
                readFile.close( );
            }catch(IOException ex){

            }    
        }

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

          try{

                FileOutputStream writeFile = new FileOutputStream("write.txt");
　　　　　　　　　/*可以指定从键盘输入*/
                String s = "happy new year!happy everyday!" +"\n"+"wish fulfillment!"+"\n"+"你好\nEnd of file stream\n";
                byte[ ] bytes = s.getBytes( ); 
                writeFile.write(bytes);
                //writeFile.write(bytes,0,s.length());    */
                writeFile.close( );
                }catch(IOException ex){

                }
          try{

                FileOutputStream writeFile = new FileOutputStream("write.txt");
                String s = "happy new year!happy everyday!" +"\n"+"wish fulfillment!"+"\n"+"你好\nEnd of file stream\n";
                for (int i = 0;i<s.length( );i++){
                    writeFile.write(s.charAt(i));
                }
                writeFile.close( );
                }catch(IOException ex){

               }    
}

FilterInputStream和FilterOutputStream，把输入流和输出流提供的功能扩大
    使用Filtered Stream提供的功能，必须首先提供Filter Stream加工的对象

    FilterInputStream
        BufferedInputStream extends FilterInputStream
            为读取的数据申请一份可用的缓冲区，用于提高输入处理的效率。
        DataInputStream extends FilterInputStream
            从流中读取基本型别(int、char、long等)的数据.
        DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(" c:\\Data.txt")  ) ) ;
    
    Filtered outputStream
        BufferedOutputStream extends FilteroutputStream
            调用flush( )来清除缓冲区内容。
        DataOutputStream extends FilteroutputStream
            将各种基本型别的数据写至流。
        DataOutputStream out =new DataOutputStream(new BufferedOutputStream(new FileOutputStream(“c:\\Data.txt") ))   ;

利用FileReader类读取纯文本文件”text.txt” 。 
    public static void main(String args[]) throws IOException{
    
        char c[ ]=new char[500];        　　　　　　　　　　　　//创建可容纳500个字符的数组

        FileReader r=new FileReader("c:\\7\\test.txt");     //创建对象r

        int num=r.read(c);      　　　　　　　　　　　　　　　　//将数据读入字符数组c内，并返回读取的字符数

        String str=new String(c,0,num);   　　　　　　　　　　//将字符串数组转换成字符串

        System.out.println("读取的字符个数为："+num+"，其内容如下：");

        System.out.println(str);
    }

利用FileWriter类将字符数组与字符串写到文件里。
    public static void main(String args[]) throws IOException{
    
        FileWriter fw=new FileWriter("c:\\7\\test2.txt");
        char c[ ]={‘H‘,‘e‘,‘l‘,‘l‘,‘o‘,‘\r‘,‘\n‘};
        String str="欢迎使用Java！";
        fw.write(c);   　　　　　　 //将字符数组写到文件里
        fw.write(str);  　　　　　　//将字符串写到文件里
        fw.close();  
    }

    BufferedReader  stdIn =  new BufferedReader(new InputStreamReader(System.in))
    String  input = stdIn.readLine( ); 
    从文件中读取一行字符串：
        BufferedReader fileIn = new BufferedReader(new FileReader(filename));
        String  line =   fileIn.readLine();
        while (line != null)  {          
            line = fileIn.readLine( );
        }
    
    public class Demo {
      public static void main(String[ ] args) throws IOException{
          try{
                   BufferedReader fileIn =                                          
                  new BufferedReader(new FileReader("c:\\7\\2.txt"));
                   String  line =   fileIn.readLine( );
                   while (line != null)  {     
                      System.out.println(line);   
                      line = fileIn.readLine( );
                    }
                   }catch(IOException ex){
                }        
         }
    }

    BufferedWriter writer = new BufferedWriter(new FileWriter(“c:\\IODemo.out"))

    public static void main(String[ ] args) throws IOException{
        try{
            BufferedReader stdin =new BufferedReader(new      InputStreamReader(System.in)); 
            System.out.print("Enter a filename:");
            String s=stdin.readLine( );
            BufferedWriter out1 = new BufferedWriter(new FileWriter(s));
            System.out.print("输入5行数据结束!");
            for(int i =0;i<5;i++){
                s=stdin.readLine( );
                out1.write(s);
                out1.newLine( );
            }   
            out1.flush( );  
            out1.close( );
        }catch(IOException ex){
        
        }
    }