1、编码规则

java.net

Class URLEncoder

• java.lang.Object
• • java.net.URLEncoder

• ---

  public class URLEncoder
  extends Object

  Utility class for HTML form encoding. This class contains static methods for converting a String to the
  application/x-www-form-urlencoded MIME format. For more information about HTML form encoding, consult the HTML
  specification.

  When encoding a String, the following rules apply:

  • The alphanumeric characters "a" through "z", "A" through "Z" and "0" through "9" remain the same.
  • The special characters ".", "-", "*", and "_" remain the same.
  • The space character " " is converted into a plus sign "+".
  • All other characters are unsafe and are first converted into one or more bytes using some encoding scheme. Then each byte is represented by the 3-character string "%xy", where
    xy is the two-digit hexadecimal representation of the byte. The recommended encoding scheme to use is UTF-8. However, for compatibility reasons, if an encoding is not specified, then the default encoding of the platform is used.

  For example using UTF-8 as the encoding scheme the string "The string ü@foo-bar" would get converted to "The+string+%C3%BC%40foo-bar" because in UTF-8 the character ü is encoded as two bytes C3 (hex) and BC (hex), and the character
  @ is encoded as one byte 40 (hex).

  Since:

  JDK1.0

• • Method Summary

    Methods 

    Modifier and Type	Method and Description
    static String	encode(String s) Deprecated. The resulting string may vary depending on the platform‘s default encoding. Instead, use the encode(String,String) method to specify the encoding.
    static String	encode(String s, String enc) Translates a string into application/x-www-form-urlencoded format using a specific encoding scheme.

    • Methods inherited from class java.lang.Object

      clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    //解释一下：这是jdk1.7里面的官方说明。大致的意思是，URLEncode是将字符串转换为application/x-www-form-urlencoded MIME格式。

  • 规则如下：1、字母和数字保持原样；
  • 2、"."、"-"、"*"和"_"保持原样；空格转换为“+”；
  • 3、其他字符转换为一个或者多个字节码，如%AB这种格式；

  例子：The string ü@foo-bar用utf-8编码为The+string+%C3%BC%40foo-bar

2、编码方法

有两个方法：encode（String s）和encode（String s，String encode）

encode（String s）用平台默认的编码方式进行编码，谨慎使用！

encode（String s，String enc）用指定的编码方式进行编码，最好使用此方式，指定编码格式，以免随着环境的变幻而产生中文乱码