JSP过滤器的应用编码过滤器

过滤器是向 Web 应用程序的请求和响应处理添加功能的Web 服务组件。
过滤器生命周期的各个阶段：
实例化->初始化--->过滤--->销毁
•过滤器必须实现javax.servlet.Filter接口,该接口中有
–init(…)
•参数类型：FilterConfig（初始化参数对象）
–doFilter(…)
•参数有三个类型分别是：ServletRequest，ServletResponse，FilterChain
–destroy()
在SRC下创建一个filter包创建一个filterEncoding类继承filter接口

[html] package 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;

/**
* @author Administrator
*字符编码的过滤器
*/
public class filterEncoding implements Filter {
    private String requestEncoding="";
    private String responseEncoding="";

    public void destroy() {
        // TODO Auto-generated method stub
        System.out.println("字符编码过滤器销毁！");
    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        // TODO Auto-generated method stub
//      System.out.println("编码过滤器运行中。。。");
        //获取过滤链
        request.setCharacterEncoding(requestEncoding);
        response.setContentType(responseEncoding);
        //执行过滤链
        chain.doFilter(request, response);

    }

    public void init(FilterConfig conif) throws ServletException {
        // TODO Auto-generated method stub
        System.out.println("字符编码过滤器初始化！");
        //初始化时获取web.xml中的数据
        requestEncoding=conif.getInitParameter("requestEncoding");
        responseEncoding=conif.getInitParameter("responseEncoding");

    }

}

package 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;

/**
* @author Administrator
*字符编码的过滤器
*/
public class filterEncoding implements Filter {
private String requestEncoding="";
private String responseEncoding="";

public void destroy() {
// TODO Auto-generated method stub
System.out.println("字符编码过滤器销毁！");
}

public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain) throws IOException, ServletException {
  // TODO Auto-generated method stub
//  System.out.println("编码过滤器运行中。。。");
  //获取过滤链
  request.setCharacterEncoding(requestEncoding);
  response.setContentType(responseEncoding);
  //执行过滤链
  chain.doFilter(request, response);

}

public void init(FilterConfig conif) throws ServletException {
  // TODO Auto-generated method stub
  System.out.println("字符编码过滤器初始化！");
  //初始化时获取web.xml中的数据
  requestEncoding=conif.getInitParameter("requestEncoding");
  responseEncoding=conif.getInitParameter("responseEncoding");

}

}
接着在web.xml中配置
[plain] 
<filter>
<filter-name>filterEncoding</filter-name>
<filter-class>filter.filterEncoding</filter-class>
<init-param>
   <param-name>requestEncoding</param-name>
   <param-value>utf-8</param-value>
</init-param>
<init-param>
   <param-name>responseEncoding</param-name>
   <param-value>text/html;charset=utf-8</param-value>
</init-param>
</filter>

<filter-mapping>
<filter-name>filterEncoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 编码过滤器结束 --

补充：Web开发 , Jsp ,

JSP过滤器的应用 编码过滤器

JSP过滤器的应用编码过滤器