struts2修改request里的参数值parameter

本文章参考了网上一些代码，经本人实验没有问题

request处于安全考虑是不能直接修改的，所以要自定义一个request继承他的类。下面是代码

import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Vector;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class MyRequest extends HttpServletRequestWrapper {
    
    private Map<String , String[]> params = new HashMap<String, String[]>();
 
 
    @SuppressWarnings("unchecked")
    public MyRequest(HttpServletRequest request) {
        // 将request交给父类，以便于调用对应方法的时候，将其输出，其实父亲类的实现方式和第一种new的方式类似
        super(request);
        //将参数表，赋予给当前的Map以便于持有request中的参数
        this.params.putAll(request.getParameterMap());
    }
    //重载一个构造方法
    public MyRequest(HttpServletRequest request , Map<String , Object> extendParams) {
        this(request);
        addAllParameters(extendParams);//这里将扩展参数写入参数表
    }
    public Map<String , String[]> getParameterMap() {  
        return params;  
    }  
  
    public Enumeration getParameterNames() {  
        Vector l = new Vector(params.keySet());  
        return l.elements();  
    }  
    @Override
    public String getParameter(String name) {//重写getParameter，代表参数从当前类中的map获取
        String[]values = params.get(name);
        if(values == null || values.length == 0) {
            return null;
        }
        return values[0];
    }
    
    public String[] getParameterValues(String name) {//同上
         return params.get(name);
    }
 
   public void addAllParameters(Map<String , Object>otherParams) {//增加多个参数
        for(Map.Entry<String , Object>entry : otherParams.entrySet()) {
            addParameter(entry.getKey() , entry.getValue());
        }
    }
 
 
    public void addParameter(String name , Object value) {//增加参数
        if(value != null) {
            if(value instanceof String[]) {
                params.put(name , (String[])value);
            }else if(value instanceof String) {
                params.put(name , new String[] {(String)value});
            }else {
                params.put(name , new String[] {String.valueOf(value)});
            }
        }
    }
    
    public void removeParameter(String name) {
    	if(params.get(name)!=null) {
    	params.remove(name);
    	}
    }
}

这个时候我们重写了request,关键在于要让action的request变成自定义的action.有两个常用的方法：

1.拦截器

<interceptors>
	<interceptor name="hh" class="handChangeInterceptor">
	<param name="includeMethods">modifyCarrierDo</param> 
	</interceptor>
	<interceptor-stack name="xxx">
	<interceptor-ref name="default"></interceptor-ref>
	<interceptor-ref name="hh"></interceptor-ref>
	</interceptor-stack>
	</interceptors>
<action name="" class="" method="">
<interceptor-ref name="xxx"></interceptor-ref>
</action>

注意自定义的拦截器要放在默认拦截器后面，因为默认拦截器完成了request,respose,parameter,actioncontext,valuestack等很多东西的数据绑定。

interceptor代码

import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.ServletActionContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import net.sf.json.JSONArray;
@Component
public class HandChangeInterceptor extends ManagementAction<DeliveryOutbound> implements Interceptor{
	
	@Override
	public void destroy() {
	}

	@Override
	public void init() {
	}
	@Override
	public String intercept(ActionInvocation arg0) throws Exception {
		System.out.println("拦截器，启动！");
		
		HttpServletRequest request =
				(HttpServletRequest) arg0.getInvocationContext().get(ServletActionContext.HTTP_REQUEST);
        ......
        ......
        ......
		MyRequest requestWrapper = new MyRequest((HttpServletRequest)request);
		requestWrapper.addParameter("xxx" , xxx);
		ServletActionContext.setRequest(requestWrapper);
		ActionContext.getContext().put(ServletActionContext.HTTP_REQUEST, requestWrapper);
		arg0.getInvocationContext().put(ServletActionContext.HTTP_REQUEST, requestWrapper);
		
		return arg0.invoke();
	}
	
}

可以看到有很多修改request，具体是用哪一个，取决于action里面是怎么拿到request的。然后用自定义的request替换掉原有的request，这样传给action就是你自己的request了，注意了注意了，如果你的项目比较怪异，比如action不是通过任何任何一种方法获取request,那拦截器可能就不行了。过滤器就是最好的选择

2.过滤器

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.List;

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.http.HttpServletRequest;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import net.sf.json.JSONArray;
@Component
public class MyFilter implements Filter{

	@Override
	public void destroy() {
		
	}
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
			System.out.println("过滤器，启动！");
		......
        ......
        ......
		MyRequest requestWrapper = new MyRequest((HttpServletRequest)request);
		requestWrapper.addParameter("xxx" , xxx);
		chain.doFilter(requestWrapper, response);
		//不给通过的话就用request转发或重定向，是ajax请求，就是下面：
        //PrintWriter out = response.getWriter(); 
		//	out.print("xxx");//返回一个标识给前端
		//	out.flush();
		//	out.close();
	
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		
	}

}

web.xml

<filter>
	<filter-name>myfilter</filter-name>
	<filter-class>
	xxx.xxx.xxx.xxx.xxx.xxx.xxx.xxx.xxx
	</filter-class>
	</filter>
	<filter-mapping>
	<filter-name>myfilter</filter-name>
	<url-pattern>/xxx/xxx.action</url-pattern>
	</filter-mapping>

一般用这个不会出现问题，因为这个是request的根源