servlet利用拦截器改写request和response

这些天在对一个项目进行二次开发，要对输入和输出的数据做一些修改，但是上一个开发人员没有进行良好的封装，所有数据直接从request.getParameter()，获取，然后response.getWrite()直接进行输出操作,如果我要一个一个程序去修改的话，应用程序上40多个servlet都得改程序，第一工作量比较大，第二自己看着恶心，以后出了问题BOSS还得找我，所以干脆想了个办法，利用拦截器继承改写request和response，这样所有进入应用程序的数据都在我的掌控下了。具体实现见如下代码！

 

1.web.xml的拦截器配置

 

  		changeResponseFilter
  		*.filter.ChangeResponseFilter
  	
  	
  		changeResponseFilter
  		*
  	

 

 

 

2.拦截器实现

 

 

package com.bjfulei.robo.machine.filter;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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 javax.servlet.http.HttpServletResponse;

import com.bjfulei.robo.machine.util.ThreeDES;
import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;

import BO.inter.param.InGeneralParam;
import BO.systools.ListMgr;
import net.sf.json.JSONObject;


/***
* mail: [email protected]
* date: 2016年8月23日 下午6:54:58 
*/


public class ChangeResponseFilter implements Filter {

	public void destroy() {

	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		MyResponseWrapper responseWrapper = new MyResponseWrapper((HttpServletResponse) response);
		MyRequestWrapper requestWrapper = new MyRequestWrapper((HttpServletRequest) request);
		
		
		chain.doFilter(requestWrapper, responseWrapper);
		MyWriter writer = responseWrapper.getMyWriter();
		
		if (writer != null) {
			String content = writer.getContent();
			response.getWriter().write(ListMgr.string2Unicode2(content));
			response.getWriter().flush();
			response.getWriter().close();
		}
		
	}

	public void init(FilterConfig arg0) throws ServletException {
		
	}

}

 

 

 

3.request改写类

 

 

package com.bjfulei.robo.machine.filter;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

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

public class MyRequestWrapper extends HttpServletRequestWrapper {
	private Map paramMap;
	
	public MyRequestWrapper(HttpServletRequest request) {
		super(request);
		paramMap =getParameterMap(request);
	}
	
	/**
	 * FIXME 修改后的获取参数方法
	 * @param name
	 * @return
	 */
	public String getParameter(String name){
		return paramMap.get(name);
	}
	
	/**
	 * FIXME 修改参数值的方法
	 * @param name
	 * @return
	 */
	public String updateParameter(String name,String value){
		return paramMap.put(name,value);
	}
	
	
	public Map getParameterMap(){
		return paramMap;
	}
	
	
	@SuppressWarnings("rawtypes")
	public static Map getParameterMap(HttpServletRequest request) {
	    // 参数Map
	    Map properties = request.getParameterMap();
	    // 返回值Map
	    Map returnMap = new HashMap();
	    Iterator entries = properties.entrySet().iterator();
	    Map.Entry entry;
	    String name = "";
	    String value = "";
	    while (entries.hasNext()) {
	        entry = (Map.Entry) entries.next();
	        name = (String) entry.getKey();
	        Object valueObj = entry.getValue();
	        if(null == valueObj){
	            value = "";
	        }else if(valueObj instanceof String[]){
	            String[] values = (String[])valueObj;
	            for(int i=0;i

 

 

 

 

 

 

4.response改写类

 

 

package com.bjfulei.robo.machine.filter;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

public class MyResponseWrapper extends HttpServletResponseWrapper {
	private MyWriter myWriter;
	
	public MyResponseWrapper(HttpServletResponse response) {
		super(response);
		try {
			myWriter = new MyWriter(response.getWriter());
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	@Override
	public PrintWriter getWriter() throws IOException {
		return myWriter;
	}

	public MyWriter getMyWriter() {
		return myWriter;
	}
	
}

 

 

package com.bjfulei.robo.machine.filter;

import java.io.PrintWriter;

public class MyWriter extends PrintWriter{
	private StringBuilder buffer;

	public MyWriter(PrintWriter out) {
		super(out);
		buffer = new StringBuilder();
	}

	@Override
	public void write(char[] buf, int off, int len) {
		// super.write(buf, off, len);
		char[] dest = new char[len];
		System.arraycopy(buf, off, dest, 0, len);
		buffer.append(dest);
	}

	@Override
	public void write(char[] buf) {
		super.write(buf);
	}

	@Override
	public void write(int c) {
		super.write(c);
	}

	@Override
	public void write(String s, int off, int len) {
		super.write(s, off, len);
	}

	@Override
	public void write(String s) {
		//super.write(s);
		buffer.append(s);
	}
	
	public String getContent(){
		return buffer.toString();
	}
	
	public void flush(){
	    
	}
	public void close(){
	    
	}
}

 

利用拦截器实现了所有输入输出数据流的自定义，分享到博客来，希望对新手有所帮助！