Methods of solving post garbled and get garbled in Web project

Prerequisites to review the causes of coding problems:

1. What is URL encoding?

URL encoding is a format that the browser uses to package form input, and the browser obtains all of the name and its corresponding value from the form, sending them as part of the URL as a name/value encoding or separating it to the server.

2. URL encoding rules.

Each pair of Name/value is separated by &, and each pair of name/value from the form is separated by =. If the user does not enter a value, the name will still appear but there is no value.

URL encoding is preceded by the hexadecimal number of the ASCII code of the character plus%. For example \ (her hexadecimal number is represented as 5c) the URL encoding is%5c.

3. Simple description of garbled and HTTP requests

In fact, do web development garbled problem is often appear, with the above code based on the following to see garbled.

1) garbled problem is often encountered in the web development process, the main reason is that the use of non-ASCII code in the URL causes the server background program parsing garbled problem.

2) The easiest place to appear in the URL is in the QueryString parameter value and Servletpath.

3) Simply use a diagram to illustrate the flow of HTTP requests:

The first step: the browser to encode the URL to the server;

The second step: the server will decode these requests after processing the display of the contents of the code sent to the client browser;

Step three: The browser displays the webpage according to the specified encoding

4) Detailed analysis of how get submissions are encoded and how the server decodes and garbled solutions

For the Get method, we know that its commit is to append the request data to the URL as a parameter, so the dependency garbled will be easy to appear, because the data name and value is likely to be passed as non-ASCII code.

When the URL is spliced, the browser encode it and then sends it to the server. See URL encoding rules for specific rules.

Here in detail the process of encode prone to problems, in this process we have to understand the need for URL encode characters are generally non-ASCII characters, so we can know that garbled main URL is appended with Chinese or special characters made, another to know the URL Encode exactly what encoding to encode the character, in fact, this encoding method is determined by the browser, different browsers and the same browser different settings affect the URL encoding, so in order to avoid the code we do not need, We can control it uniformly through Java code or javaspcript code.

After the URL encode is completed, the URL becomes a character in the ASCII range, and then it is converted to binary with the ISO-8859-1 encoding to send it along with the request header.

After the server, the first server will be decoded with iso-8859-1, the server gets the data is the ASCII range of the request header characters, where the request URL with parameter data, if it is a central defender or special characters, then the encode after the% XY (hexadecimal number in the encoding rule) is not working by request.setcharacterencoding (). At this time we can find the root cause of garbled is that the client is generally by using UTF-8 or GBK data to encode, to the server but iso-8859-1 way decoder obviously not.

There are two ways to solve this problem.

One: The encoding is translated by the GetBytes method of the string class, with the specific Java code:

New String (Request.getparameter ("name"). GetBytes ("Iso-8859-1"), "Client encoding Mode")

The second type: Change the configuration information in the server XML code:

<connector port= "8080" protocol= "http/1.1" maxthreads= "20000" connectiontimeout= "

Redirectport= "8443" uriencoding= "Client Encoding"/>

5) detailed analysis of how the post submission is encoded and how the server decodes and garbled the solution

For post, the parameter value pairs in the form are sent to the server via the request packets, at which point the browser will be based on the ContentType of the page ("text/html; CHARSET=GBK ") encodes the data in the form and then sends it to the server.

In the server-side program we can

Request.setcharacterencoding () sets the encoding and then passes the

Request.getparameter get the right data.

Garbled here can be directly solved by request.setcharacterencoding ().

The second way is to add the filter in the Web. XML to solve the post garbled problem.

Post garbled problem in Web project:

Post garbled causes:

<form id= "Itemform" action= "${pagecontext.request.contextpath}/item/editsubmit.action" method= "POST" Enctype= "Multipart/form-data" >

Use the Post method in form form, this time

Add to Web. xml:

<filter>

<filter-name>CharacterEncodingFilter</filter-name>

<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>

<init-param>

<param-name>encoding</param-name>

<param-value>UTF-8</param-value>

</init-param>

</filter>

<filter-mapping>

<filter-name>CharacterEncodingFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

The above can solve the POST request garbled problem.

Cause of Get garbled:

The character of the JSP page in Eclipse is Utf-8, and the character of the middleware server server is iso-8859-1, and the browser character is Utf-8, which is caused by get garbled. Browser access is generally the form of get.

Get garbled in Web project, modify Tomcat's encoding: Tomcat default encoding is Iso-8859-1

There are two garbled methods for GET request Chinese parameter:

Modify the Tomcat profile add code to match the project code as follows:

<connector uriencoding= "utf-8" connectiontimeout= "20000" port= "8080" protocol= "http/1.1" redirectport= " 8443 "/>

Another way to re-encode parameters:

String UserName New

String (Request.getparamter ("UserName"). GetBytes ("Iso8859-1"), "Utf-8")

Iso8859-1 is the tomcat default encoding, and the Tomcat encoded content needs to be encoded by utf-8

Methods of solving post garbled and get garbled in Web project