Why is the java.net. urlencoder. encode method called twice instead of once?

In JSP, the encoding method of UTF-8 is used for Chinese encoding, And the request is called in servlet. the getparameter (); method is automatically decoded using the encoding format specified by the server. Therefore, the front-end encoding is decoded once at the backend, and the decoding method is different from the encoding method, causing garbled characters, so it takes two times.

Searchbean. setkeyword (urlencoder. encode (urlencoder. encode (searchbean. getkeyword (), "UTF-8"), "UTF-8 "));

String keyword = urldecoder. Decode (getparam ("keyword"), "UTF-8 ");