过滤器和拦截器的使用

1.创建请求编码的过滤器

package com.ch.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;

public class EncodeFilter implements Filter {

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        
    }

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

         request.setCharacterEncoding("utf-8");  
         chain.doFilter(request, response);  
        
        
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
        
    }

}

1.2在web.xml中进行配置

<!-- 过滤器配置 -->
    <filter>
        <filter-name>encorder</filter-name>
        <filter-class>com.ch.filter.EncodeFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>encorder</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

2.创建关于用户登录拦截的拦截器

package com.ch.intercept;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ActionProxy;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

public class CheckedUser  extends AbstractInterceptor{

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        
        // 获取ActionContext对象
                ActionContext ac = invocation.getInvocationContext();
                
                // 获取action的代理对象
                 ActionProxy proxy = invocation.getProxy();
                 // 获取当前执行的方法名
                 String methodName = proxy.getMethod();
                 // 判断
                 if (!"login".equals(methodName)) {
                     if("register".equals(methodName)){
                         
                         // 说明当前用户正在注册
                         return invocation.invoke(); 
                     }else{
                     // 先获取当前登陆的用户
                     Object obj = ac.getSession().get("username");
                     if (obj == null) {
                         // 没有登陆
                         return "input";
                     } else {
                         // 当前用户有登陆
                         return invocation.invoke();
                     }
                     }
                 } else {
                     // 说明当前用户正在登陆
                     return invocation.invoke();
                 }

        
        
    }

}

2.1在struts.xml中进行配置

<!-- 【拦截器配置】 -->
        <interceptors>
            <interceptor name="loginCheck" class="com.ch.intercept.CheckedUser"></interceptor>
            <interceptor-stack name="myStack">
                <interceptor-ref name="defaultStack"></interceptor-ref>
                <interceptor-ref name="loginCheck"></interceptor-ref>
            </interceptor-stack>
        </interceptors>

<default-interceptor-ref name="myStack"></default-interceptor-ref>