Java基础总结IO流

Posted 2020-09-30

字节流

1. InputStream 字节输入流

代码演示

 1     InputStream in = System.in;
 2     
 3     System.out.println("int read(byte b) 方法演示");
 4     //int read()
 5     int bt = 0;
 6     while((bt=in.read())>0){    
 7         System.out.print(bt+" ");
 8         if(bt == 10){    //回车\\r(13) 换行\\n(10)
 9             break;
10         }
11     }
12     System.out.println("\\n\\rint read(byte[] buffer) 方法演示");
13 
14     //int read(byte[] buffer)
15     int length = 0;
16     byte[] buffer = new byte[10];
17     while((length=in.read(buffer)) != 0){
18         for(int i=0; i<length; i++){
19             System.out.print(buffer[i]+" ");
20         }
21         break;
22     }
23     
24     System.out.println("\\n\\rint read(byte[] buffer, int offset, int len) 方法演示");
25     
26     //int read(byte[] buffer, int offset, int len)
27     int len = 1024;
28     int count = 0;
29     byte[] buf = new byte[len];
30     while((count=in.read(buf, 0, len))>0){
31         for(int i=0; i<count; i++){
32             System.out.print(buf[i]+" ");
33         }
34         break;
35     }
36     in.close();

 

2. OutputStream 字节输出流

 

代码演示

 1     OutputStream out = System.out;
 2     //void write(int b)
 3     out.write(65);    //字符A
 4     
 5     out.write(13);    //回车 \\r
 6     out.write(10);    //换行 \\n
 7     
 8     //flush()
 9     out.flush();
10     
11     //write(byte[] bytes)
12     byte[] bytes = new String("张晓明").getBytes();
13     out.write(bytes);
14     
15     out.write(13);    //回车 \\r
16     out.write(10);    //换行 \\n
17     
18     //write(byte[] bytes, int offset, int length)
19     bytes = new String("zhangxiaoming").getBytes();
20     out.write(bytes, 5, 8);
21     
22     out.close();

 

字符流

1. Reader 字符输入流

代码演示

 1     Reader reader = new InputStreamReader(System.in);
 2     
 3     //int read()
 4     System.out.println("int read() 方法演示");
 5     int c;
 6     while((c=reader.read()) != 13){
 7         System.out.print((char)c);
 8     }
 9     reader.read();
10     
11     //int read(char[] buf)
12     System.out.println("\\n\\rint read(char[] buf) 方法演示");
13     int count = 0;
14     char[] buf = new char[1024];
15     while((count=reader.read(buf)) > 0){
16         String str = new String(buf, 0, count);
17         if(str.indexOf("stop")>=0) break;
18         System.out.print(str);
19     }
20     
21     //int read(char[] buffer, int offset, int len)
22     System.out.println("\\n\\rint read(char[] buffer, int offset, int len) 方法演示");
23     int length = 1024;
24     char[] buffer = new char[length];
25     while((count=reader.read(buffer, 0, length)) > 0){
26         String str = new String(buffer, 0, count);
27         if(str.indexOf("stop")>=0) break;
28         System.out.print(str);
29     }

 

2. Writer 字符输出流

 

代码演示

 1     Writer writer = new OutputStreamWriter(System.out);
 2     String str = "中国";
 3     
 4     //write(String str) 写入字符串
 5     writer.write(str);
 6     
 7     //write(int c)    写入单个字符
 8     writer.write(10);    //换行符
 9     
10     //write(String str, int offset, int length) 写入部分字符串
11     writer.write(str, 0, 1);
12     
13     writer.write(10);
14     
15     //write(char[] buf)    写入字符数组
16     char[] chars = str.toCharArray();
17     writer.write(chars);
18     
19     writer.write(10);
20     
21     //write(char[] buf, int offset, int length) 写入部分字符数组
22     writer.write(chars, 0, 1);
23     writer.write(10);
24     
25     writer.flush();
26     
27     //append(char c) 追加字符
28     writer.append(‘z‘);
29     writer.write(10);
30     
31     String str2 = "中华人民共和国";
32     //append(CharSequence csq)
33     writer.append(str2);
34     writer.write(10);
35     
36     //append(CharSequence csq, int offset, int length)
37     writer.append(str2, 0, 4);
38     
39     writer.close();