Form encoding filter

If Spring is used, you can replace it with org. springframework. web. filter. CharacterEncodingFilter.
[Html]
<? Xml version = "1.0" encoding = "UTF-8"?>
<Web-app version = "2.5" xmlns = "http://java.sun.com/xml/ns/javaee"
Xmlns: xsi = "http://www.w3.org/2001/XMLSchema-instance"
Xsi: schemaLocation = "http://java.sun.com/xml/ns/javaee
Http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd>
<Filter>
<Filter-name> EncodingFilter </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> EncodingFilter </filter-name>
<Url-pattern>/* </url-pattern>
</Filter-mapping>
</Web-app>

The following figure shows the web. xml configuration in the JavaWeb project.
[Html
<? Xml version = "1.0" encoding = "UTF-8"?>
<Web-app version = "2.5"
Xmlns = "http://java.sun.com/xml/ns/javaee"
Xmlns: xsi = "http://www.w3.org/2001/XMLSchema-instance"
Xsi: schemaLocation = "http://java.sun.com/xml/ns/javaee
Http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd>
<Filter>
<Filter-name> EncodingFilter </filter-name>
<Filter-class> com. jadyer. Filter. CharacterEncodingFilter </filter-class>
<Init-param>
<Param-name> encoding </param-name>
<Param-value> UTF-8 </param-value>
</Init-param>
</Filter>
<Filter-mapping>
<Filter-name> EncodingFilter </filter-name>
<Url-pattern>/* </url-pattern>
</Filter-mapping>
</Web-app>

The following is the CharacterEncodingFilter. java filter used to set the form transmission parameter encoding.
[Java]
Package com. jadyer. Filter;
 
Import java. io. IOException;
 
Import javax. servlet. Filter;
Import javax. servlet. FilterChain;
Import javax. servlet. FilterConfig;
Import javax. servlet. ServletException;
Import javax. servlet. ServletRequest;
Import javax. servlet. ServletResponse;
 
/**
* Sets the encoding of transmission parameters.
*/
Public class CharacterEncodingFilter implements Filter {
Private String encoding = "ISO8859_1 ";
 
/**
* When the filter object is destroyed, the Web Container calls this method.
* @ See this method is mainly used to release the resources occupied by the filter object.
*/
Public void destroy (){}

/**
* The Web Container calls the filter object when the filter object is generated. It is mainly used to initialize the filter.
* @ See this method receives a FilterConfig-type parameter to obtain information about the current filter.
* @ See. For example, you can call the getFilterName () method of FilterConfig to obtain the name of the filter.
* @ See. For example, call the getServletContext () method to obtain the current ServletContext object.
* @ See here is mainly used to read the value of <param-name> encoding </param-name> set in web. xml.
*/
Public void init (FilterConfig config) throws ServletException {
Encoding = config. getInitParameter ("encoding ");
}
 
/**
* The doFilter () method is the core method in the Filter interface. It completes the Filter function.
* @ See FilterChain objects are objects that save the execution sequence of multiple filters.
* @ See a Web application can contain multiple filters. These filters are like beads being stringed together.
* @ See is called one by one. The call sequence is the order in which the filter is declared in web. xml.
* @ See: by calling the doFilter () method of the FilterChain object, you can call the doFilter () method of the next filter.
* @ See if the next filter is the last one, the Servlet, JSP, or other files requested by the client are called.
*/
Public void doFilter (ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
Request. setCharacterEncoding (encoding); // sets the form parameter encoding method.
Chain. doFilter (request, response );
}
}