【Java基础总结】IO流

字节流

1. InputStream 字节输入流

代码演示

     InputStream in = System.in;

     System.out.println("int read(byte b) 方法演示");
     //int read()
     int bt = 0;
     while((bt=in.read())>0){
         System.out.print(bt+" ");
         if(bt == 10){    //回车\r(13) 换行\n(10)
             break;
         }
     }
     System.out.println("\n\rint read(byte[] buffer) 方法演示");

     //int read(byte[] buffer)
     int length = 0;
     byte[] buffer = new byte[10];
     while((length=in.read(buffer)) != 0){
         for(int i=0; i<length; i++){
             System.out.print(buffer[i]+" ");
         }
         break;
     }

     System.out.println("\n\rint read(byte[] buffer, int offset, int len) 方法演示");

     //int read(byte[] buffer, int offset, int len)
     int len = 1024;
     int count = 0;
     byte[] buf = new byte[len];
     while((count=in.read(buf, 0, len))>0){
         for(int i=0; i<count; i++){
             System.out.print(buf[i]+" ");
         }
         break;
     }
     in.close();

2. OutputStream 字节输出流

代码演示

     OutputStream out = System.out;
     //void write(int b)
     out.write(65);    //字符A

     out.write(13);    //回车 \r
     out.write(10);    //换行 \n

     //flush()
     out.flush();

     //write(byte[] bytes)
     byte[] bytes = new String("张晓明").getBytes();
     out.write(bytes);

     out.write(13);    //回车 \r
     out.write(10);    //换行 \n

     //write(byte[] bytes, int offset, int length)
     bytes = new String("zhangxiaoming").getBytes();
     out.write(bytes, 5, 8);

     out.close();

字符流

1. Reader 字符输入流

代码演示

     Reader reader = new InputStreamReader(System.in);

     //int read()
     System.out.println("int read() 方法演示");
     int c;
     while((c=reader.read()) != 13){
         System.out.print((char)c);
     }
     reader.read();

     //int read(char[] buf)
     System.out.println("\n\rint read(char[] buf) 方法演示");
     int count = 0;
     char[] buf = new char[1024];
     while((count=reader.read(buf)) > 0){
         String str = new String(buf, 0, count);
         if(str.indexOf("stop")>=0) break;
         System.out.print(str);
     }

     //int read(char[] buffer, int offset, int len)
     System.out.println("\n\rint read(char[] buffer, int offset, int len) 方法演示");
     int length = 1024;
     char[] buffer = new char[length];
     while((count=reader.read(buffer, 0, length)) > 0){
         String str = new String(buffer, 0, count);
         if(str.indexOf("stop")>=0) break;
         System.out.print(str);
     }

2. Writer 字符输出流

代码演示

     Writer writer = new OutputStreamWriter(System.out);
     String str = "中国";

     //write(String str) 写入字符串
     writer.write(str);

     //write(int c)    写入单个字符
     writer.write(10);    //换行符

     //write(String str, int offset, int length) 写入部分字符串
     writer.write(str, 0, 1);

     writer.write(10);

     //write(char[] buf)    写入字符数组
     char[] chars = str.toCharArray();
     writer.write(chars);

     writer.write(10);

     //write(char[] buf, int offset, int length) 写入部分字符数组
     writer.write(chars, 0, 1);
     writer.write(10);

     writer.flush();

     //append(char c) 追加字符
     writer.append('z');
     writer.write(10);

     String str2 = "中华人民共和国";
     //append(CharSequence csq)
     writer.append(str2);
     writer.write(10);

     //append(CharSequence csq, int offset, int length)
     writer.append(str2, 0, 4);

     writer.close();