//=================初学者注重，请将此文件放在WEB-INFclassesfilters下，
//注重先以SetCharacterEncodingFilter.java保存，然后编译一下，推荐使用eclipse
package myAddrBook;
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;

/**
 * @author Administrator
 *
 * TODO 要更改此生成的类型注释的模板，请转至
 * 窗口 － 首选项 － Java － 代码样式 － 代码模板
 */
public class SetCharacterEncodingFilter implements Filter {
  protected String encoding = null;
  protected FilterConfig filterConfig = null;
  protected boolean ignore = true;

  public void destroy() {
   this.encoding = null;
   this.filterConfig = null;
  }

 public void doFilter(ServletRequest request, ServletResponse response,
 FilterChain chain)
 throws IOException, ServletException {

  // Conditionally select and set the character encoding to be used
  if (ignore || (request.getCharacterEncoding() == null)) {
   String encoding = selectEncoding(request);
   if (encoding != null)
    request.setCharacterEncoding(encoding);
  }

  // Pass control on to the next filter
  chain.doFilter(request, response);

 }

 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 if (value.equalsIgnoreCase("yes"))
   this.ignore = true;
  else
   this.ignore = false;

 }

 protected String selectEncoding(ServletRequest request) {
  return (this.encoding);
 }

}

//==================这段代码是我在网上摘录的，因为不知到出处所以无法标明作者
//然后将下面<filter>开始的代码加入到web.xml中,它位于WEB-INF下。
//我的QQ：22070699
//配置web.xml

<!--  Set Character Encoding-->
   
    <filter>
  <filter-name>Set Character Encoding</filter-name>
  <filter-class>myAddrBook.SetCharacterEncodingFilter</filter-class>
  <init-param>
   <param-name>encoding</param-name>
   <param-value>GBK</param-value>
  </init-param>
 </filter>
 
 <filter-mapping>
  <filter-name>Set Character Encoding</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>
 
    <!--   Set Character Encoding-->