java IO之DataInputStream和DataOutputStream

 1 /**
 2  * 
 3  */
 4 package com.io.test;
 5 
 6 import java.io.ByteArrayInputStream;
 7 import java.io.ByteArrayOutputStream;
 8 import java.io.DataInputStream;
 9 import java.io.DataOutputStream;
10 import java.io.IOException;
11 
12 import org.junit.Test;
13 
14 /**
15  * utf-8比较省空间
16  * @author chengjj
17  * 
18  */
19 public class TestDataStream {
20 
21     @Test
22     public void testDataStream() {
23         try {
24             ByteArrayOutputStream baos = new ByteArrayOutputStream();//内存中申请一块字节数组,具体多大随即的，不用去管
25             DataOutputStream daos = new DataOutputStream(baos);
26             daos.writeDouble(Math.random());//8个字节
27             daos.writeBoolean(true);//1个字节
28             
29             
30             ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
31             System.out.println(bais.available());//一共9个字节
32             DataInputStream dais = new DataInputStream(bais);
33             //先写进去的先读出来，一定要注意
34             System.out.println(dais.readDouble());
35             System.out.println(dais.readBoolean());
36             
37         } catch (IOException e) {
38             e.printStackTrace();
39         }
40     }
41 }