Solution to garbled request in java

Problems:

When sending a request to the server through a get request, if the request parameters are in Chinese, the parameters received by the server will be garbled.

Cause analysis and solutions to garbled codes:

1. About decoding and encoding

Encoding: '中'→1110001

Decoding: 1110001→'中'

Garbled characters: Different character sets are used in the encoding and decoding processes

2. Problems with character encoding and decoding in Web applications

(1) Request process:

<1>GET request

The browser side is encoded in UTF-8, so it should also be decoded in UTF-8 on the server side

Because the GET request parameters are attached Behind the URL address, so the decoding character set of the URL address must be unified.

Solution:

Find the first connector in the tomcat configuration file server.xml and add the following attributes URIEncoding=UTF-8

<2>POST request

Execute before obtaining the request parameters: request.setCharacterEncoding("UTF-8");

(2) Response process

(1) Specify the encoding character set of the response data

(2) Tell the browser what character set should be used to decode the response data

<1>The Tomcat server will automatically set the "Encoding Character Set" according to the "Decoding Character Set"

<2>Set the encoding character set: tell the browser the content type of the current response data: response.setContentType("text/html;charset=UTF-8"); It should be noted that it needs to be specified in response.getWriter() ; set before, otherwise it will be invalid.

Suggestion:

All filters only work on POST requests. Setting the character encoding method in the jsp page only works on POST requests when the form is submitted, and does not work on GET requests. It cannot set its character encoding.

uses the default encoding method in GET requests, so for GET requests, you need to set URIEncoding="UTF-8" in the server.xml file and then restart TOMCAT can solve the problem of Chinese garbled characters,

, but it is not recommended to pass Chinese parameters in the href hyperlink request, nor is it recommended to pass Chinese parameters in the GET request.

In addition, a unified encoding method is implemented for the transmitted part of the Chinese language when transmitting and receiving. Use

"reply.jsp?title="+java.net.URLEncoder.encode(keywords)

when transmitting parameters, and then use keywords=new String(request.getParameter(" on the receiving parameter page) keywords").getBytes("8859_1"));Although this method temporarily solves the problem of Chinese garbled characters,

, however, the problem of Chinese garbled characters may still occur during later maintenance and deployment to other servers. , so its use is not recommended.

For Post requests, just write the following code in Servlet or jsp to solve the problem of Chinese garbled characters passed in from the form

 request.setCharacterEncoding("utf-8");

Understand:

And For Get requests, because the request parameters will be appended to the URL in the address bar, the above processing method cannot be used. It should be like this:

   String str=request.getQueryString();
   //使用URLDecoder解码字符串
   String str1=java.net.URLDecoder.decode(str,"utf-8");
   String[] paraStrings=str1.split("&");
    //paraStrings[0]就是第一个参数，依次类推...
   for(String paraString : paraStrings)
   {
         String[] nameValue=paraString.split("=");
         //nameValue[0]就是表单的name，nameValue[1]就是表单name对应的值
   }

Another way is to obtain the request parameters and then re-encode the request parameter values, that is, first convert them into a byte array, and then re-decode the byte array into a string.

  String str=request.getParameter("name");
  byte[] bytes=str.getBytes("ISO-8859-1");
  String name=new String(bytes,"utf-8");

Conclusion: When passing Chinese parameters, it is best to submit them using POST requests. Different server settings may have different encoding methods, and different operating system settings may have different encoding methods.

Recommended: java basic tutorial

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