package com.sharep.filter;//包名
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;
public class SetCharacterEncodingFilter implements Filter
{
 protected String encoding = null;
 protected FilterConfig filterConfig = null;
 protected boolean ignore = true;
 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"))
   this.ignore = true;
  else
   this.ignore = false;
 }
 public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain) throws IOException, ServletException
 {

  if (ignore || (request.getCharacterEncoding() == null))
  {
   String encoding = selectEncoding(request);
   if (encoding != null)
    request.setCharacterEncoding(encoding);
  }
  chain.doFilter(request, response);
 }
 public void destroy()
 {
  this.encoding = null;
  this.filterConfig = null;
 }
 protected String selectEncoding(ServletRequest request)
 {
  return (this.encoding);
 }
}

<filter>
  <filter-name>SetCharacterEncoding</filter-name>
  <filter-class>com.young.filter.SetCharacterEncodingFilter</filter-class>//注意這里是類名，要有完整包名
  <init-param>
   <param-name>encoding</param-name>
   <param-value>UTF-8</param-value>
  </init-param>
 </filter>

 <filter-mapping>
  <filter-name>SetCharacterEncoding</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>

String url = “jdbc:mysql://localhost:3306/test2?autoReconnect=true&useUnicode=true&characterEncoding=gbk&mysqlEncoding=utf8″ ;

show variables like ‘collation_%';