1.修改web.xml文件,在＜web-app＞标签后增加如下内容.

＜filter＞
＜filter-name＞Set Character Encoding＜/filter-name＞
＜filter-class＞com.company.demo.util.SetEncodingFilter＜/filter-class＞
＜init-param＞
＜param-name＞encoding＜/param-name＞
＜param-value＞gb2312＜/param-value＞
＜/init-param＞
＜/filter＞
＜filter-mapping＞
＜filter-name＞Set Character Encoding＜/filter-name＞
＜url-pattern＞/*＜/url-pattern＞
＜/filter-mapping＞
＜servlet＞
2.创建类文件(SetEncodingFilter.java)

package com.company.demo.util;
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;
import javax.servlet.UnavailableException;

/**
* Set All HttpRequest Encoding

*/
public class SetEncodingFilter
implements Filter {
/**
* The default character encoding to set for requests that pass through
* this filter.
*/
protected String encoding = null;

/**
* The filter configuration object we are associated with. If this value
* is null, this filter instance is not currently configured.
*/
protected FilterConfig filterConfig = null;

/**
* Should a character encoding specified by the client be ignored?
*/
protected boolean ignore = true;

/**
* Take this filter out of service.
*/
public void destroy() {
this.encoding = null;
this.filterConfig = null;
}

/**
* Select and set (if specified) the character encoding to be used to
* interpret request parameters for this request.
*
* @param request The servlet request we are processing
* @param result The servlet response we are creating
* @param chain The filter chain we are processing
*
* @exception IOException if an input/output error occurs
* @exception ServletException if a servlet error occurs
*/
public void doFilter(
ServletRequest request,
ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if (ignore
(request.getCharacterEncoding() == null)) {
request.setCharacterEncoding(selectEncoding(request));
}
chain.doFilter(request, response);
}

/**
* Place this filter into service.
* @param filterConfig The filter configuration object
*/
public void init(FilterConfig filterConfig) throws ServletException {

this.filterConfig = filterConfig;
this.encoding = filterConfig.getInitParameter("encoding");
String value = filterConfig.getInitParameter("ignore");
if (value == null)
this.ignore = true;
else if (value.equalsIgnoreCase("true")
value.equalsIgnoreCase("yes"))
this.ignore = true;
else
this.ignore = false;
}

/**
* Select an appropriate character encoding to be used, based on the
* characteristics of the current request and/or filter initialization
* parameters. If no character encoding should be set, return
* ＜code＞null＜/code＞.
* ＜p＞
* The default implementation unconditionally returns the value configured
* by the ＜strong＞encoding＜/strong＞ initialization parameter for this
* filter.
*
* @param request The servlet request we are processing
*/
protected String selectEncoding(ServletRequest request) {
return (this.encoding);
}

/**
* Returns the filterConfig.
* @return FilterConfig
*/
public FilterConfig getFilterConfig() {
return filterConfig;
}

/**
* Sets the filterConfig.
* @param filterConfig The filterConfig to set
*/
public void setFilterConfig(FilterConfig filterConfig) {
this.filterConfig = filterConfig;
}

}