1. import java.net.*; 
2. import java.io.*; 
3. import sun.misc.resources.*; 
4.  
5. public class MailClientDemo02 { 
6.  
7.     /** 
8.      * @param args 
9.      * @throws IOException  
10.      * @throws UnknownHostException  
11.      */ 
12.     public static void main(String[] args) throws UnknownHostException, IOException { 
13.         // TODO Auto-generated method stub 
14.          
15.         Socket client=null; 
16.          
17.         client=new Socket("smtp.qq.com",25); 
18.          
19.         BufferedReader buf=null; 
20.          
21.         PrintStream out=null; 
22.          
23.         out=new PrintStream(client.getOutputStream()); 
24.          
25.         buf=new BufferedReader(new InputStreamReader(client.getInputStream())); 
26.          
27.         String helo="HELO localhost"; 
28.          
29.         String auth="AUTH LOGIN"; 
30.          
31.         String username=new sun.misc.BASE64Encoder().encode("371031541@qq.com".getBytes()); 
32.          
33.         String password=new sun.misc.BASE64Encoder().encode("××××××××××".getBytes()); 
34.          
35.          
36.          
37.         //System.out.println(username+"\t"+password); 
38.          
39.         String mailFrom="MAIL FROM:371031541@qq.com"; 
40.          
41.         String rcpt="RCPT TO:qinlouke@yahoo.cn"; 
42.          
43.         String data="DATA"; 
44.          
45.         String subject="Subject:hi,java"; 
46.          
47.         String from="From:371031541@qq.com"; 
48.          
49.         String to="To:qinlouke@yahoo.cn"; 
50.          
51.         String contxt01="this is a java client"; 
52.          
53.         String contxt02="this progrom is writed by qinlouke"; 
54.          
55.         String contxt03="thanks"; 
56.          
57.         String end="."; 
58.          
59.         String quit="QUIT"; 
60.          
61.         out.println(helo); 
62.          
63.         System.out.println("服务器响应："+buf.readLine()); 
64.          
65.         out.println(auth); 
66.          
67.         System.out.println("服务器响应："+buf.readLine()); 
68.          
69.         out.println(username); 
70.          
71.         System.out.println("服务器响应："+buf.readLine()); 
72.          
73.         out.println(password); 
74.          
75.         System.out.println("服务器响应："+buf.readLine()); 
76.          
77.         out.println(mailFrom); 
78.          
79.         System.out.println("服务器响应："+buf.readLine()); 
80.          
81.         out.println(rcpt); 
82.          
83.         System.out.println("服务器响应："+buf.readLine()); 
84.          
85.         out.println(data); 
86.          
87.         System.out.println("服务器响应："+buf.readLine()); 
88.          
89.         out.println(subject); 
90.          
91.         out.println(from); 
92.          
93.         out.println(to); 
94.              
95.         out.println(""); 
96.          
97.         out.println(""); 
98.          
99.         out.println(""); 
100.              
101.         out.println(contxt01); 
102.          
103.         out.println(contxt02); 
104.          
105.         out.println(contxt03); 
106.          
107.         out.println(end); 
108.          
109.         System.out.println("服务器响应："+buf.readLine()); 
110.          
111.         out.println(quit); 
112.          
113.         System.out.println("服务器响应："+buf.readLine()); 
114.          
115.         client.close(); 
116.          
117.         buf.close(); 
118.  
119.     } 
120.  
121. } 

程序运行结果为：

qinlouke@yahoo.cn收到的邮件内容如下：