Java 网络编程3---URLEncoder与URLDecoder

旧城等待， 2022-05-20 04:56 209阅读 0赞

在`Java`中如果要完成`URL`的编码和解码操作，可以使用`URLEncoder`和`URLDecoder`两个类，`URLEncoder`可以为传递的内容进行编码，而`URLDecoder`可以为传递的内容进行解码。这两个类常用的方法如下。

<table> 
 <thead> 
  <tr> 
   <th>序号</th> 
   <th>URLEncoder类常用方法</th> 
   <th>描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td><code>public static String encode(String s, String enc)</code></td> 
   <td>使用指定的编码机制将字符串转换为 application/x-www-form-urlencoded 格式。</td> 
  </tr> 
 </tbody> 
</table>

<table> 
 <thead> 
  <tr> 
   <th>序号</th> 
   <th>URLDecoder类常用方法</th> 
   <th>描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td><code>public static String decode(String s, String enc)</code></td> 
   <td>使用指定的编码机制对 application/x-www-form-urlencoded 字符串解码。</td> 
  </tr> 
 </tbody> 
</table>

**实例：编码和解码操作**

package my.net.encoder_decoder;
    
    import java.io.UnsupportedEncodingException;
    import java.net.URLDecoder;
    import java.net.URLEncoder;
    
    public class Encode_Decode { 
        public static void main(String[] args) throws UnsupportedEncodingException
        {
            String urlStr = "file:///D:/dev/workspace/Net/%E4%B8%8A%E4%B8%80%E7%AF%87%E5%8D%9A%E5%AE%A2.html";
            String urlDecoder = URLDecoder.decode(urlStr, "utf-8");
            // 把解码的好的字符串在编程成utf-8编码
            String urlEncoderutf8 = URLEncoder.encode(urlDecoder, "utf-8");
            System.out.println("原字符串 :"+urlStr);
            System.out.println("解码后的字符串 :"+urlDecoder);
            System.out.println("重新编码为utf-8:"+urlEncoderutf8);
            System.out.println("再次解码 :"+URLDecoder.decode(urlEncoderutf8, "utf8"));
            System.out.println();
        }
    }

**运行结果：**

原字符串       :file:///D:/dev/workspace/Net/%E4%B8%8A%E4%B8%80%E7%AF%87%E5%8D%9A%E5%AE%A2.html
    解码后的字符串  :file:///D:/dev/workspace/Net/上一篇博客.html
    重新编码为utf-8:file%3A%2F%2F%2FD%3A%2Fdev%2Fworkspace%2FNet%2F%E4%B8%8A%E4%B8%80%E7%AF%87%E5%8D%9A%E5%AE%A2.html
    再次解码       :file:///D:/dev/workspace/Net/上一篇博客.html

## 中文转为Unicode字符 ##

String str = "中文";
    try
    {
        String encodeStr = URLEncoder.encode(str, "utf-16be");
        encodeStr = encodeStr.replaceAll("%(.{2})%(.{2})", "\\\\u$1$2");
        System.out.println(encodeStr);
    } catch (UnsupportedEncodingException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

运行结果:

\u4E2D\u6587