关于java的URL编码的问题（URLencode，encode）

今天看公司项目的代码，对图片发送异步请求的URL的编码问题，看了看，又查了一些资料，希望能对URL编码有疑惑的人了解一下吧。 AAAAAAAAAAAAAAAA:首先我是用java的URLencode.encode方法对其进行编码的。

它的说明是

 Encodes a given string s in a x-www-form-urlencoded string using the specified encoding schemeenc. All characters except letters ('a'..'z', 'A'..'Z') and numbers ('0'..'9') and characters '.', '-', '*', '_' are converted into their hexadecimal value prepended by '%'. For example: '#' -> #. In addition, spaces are substituted by '+' BBBBBBBBBBBBBBB:但是呢URL传输需要字符串的规则是： 1：Characters in the unreserved character set as defined by(ALPHA, DIGIT, "-", ".", "_", "~") MUST NOT be encoded. 2： All other characters MUST be encoded. 3：The two hexadecimal characters used to represent encoded characters MUST be upper case. 不知道大家看出来没有有何区别，首先URLencode.encode 是'.', '-', '*', '_'符号不编码，而URL传输需要字符串是 "-", ".", "_", "~"不编码。

那么可以这样的 String URL="www.baidu.com"; String ENCODING="utf-8"; String strURL= URLEncoder.encode(URL, ENCODING).replace("*","*").replace("~", "~").replace("+"," ");