过滤器实现去除空格、增加参数功能

环境：JDK1.7 TOMCAT7 spring3.2

 1.过滤器代码

    1.1基于spring过滤器

    

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.filter.OncePerRequestFilter;

public class SessionFilter extends OncePerRequestFilter {

	@Override
	protected void doFilterInternal(HttpServletRequest request,
			HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {
			ParameterRequestWrapper requestWrapper = new ParameterRequestWrapper(request);
	        filterChain.doFilter(requestWrapper, response);
	}
}

 

   1.2基于javax.servlet.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;
import javax.servlet.http.HttpServletRequest;

/**
 * Servlet Filter implementation class CommonFilter
 */
public class CommonFilter implements Filter {

    /**
     * Default constructor. 
     */
    public CommonFilter() {
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see Filter#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}

	/**
	 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
	 */
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		// TODO Auto-generated method stub
		// place your code here
                HttpServletRequest hr=(HttpServletRequest) request;
  
                String url = hr.getServletPath().trim();
                if (url.equals("xxx")){//不需要过滤的url，这里可以使用一个配置文件配置这些url，项目启动时读入内存一个map中，然后在这里进行判断
		    //我定义的是urlFilterMap，然后在这里urlFilterMap.containsValue(url)进行判断	
                    chain.doFilter(hr, response);
                }else{
                   ParameterRequestWrapper requestWrapper = new ParameterRequestWrapper((HttpServletRequest)request);
		   chain.doFilter(requestWrapper, response);
                }
	}

	/**
	 * @see Filter#init(FilterConfig)
	 */
	public void init(FilterConfig fConfig) throws ServletException {
		// TODO Auto-generated method stub
	}

}

 2.过滤器包装类

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
public class ParameterRequestWrapper extends HttpServletRequestWrapper {
    
    private Map<String , String[]> params = new HashMap<String, String[]>();

    @SuppressWarnings("unchecked")
	public ParameterRequestWrapper(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());
        this.modifyParameterValues();
    }
    //重载一个构造方法
    public ParameterRequestWrapper(HttpServletRequest request , Map<String , Object> extendParams) {
        this(request);
        addAllParameters(extendParams);//这里将扩展参数写入参数表
    }
    
    public void modifyParameterValues(){//将parameter的值去除空格后重写回去
    	Set<String> set =params.keySet();
    	Iterator<String> it=set.iterator();
	    while(it.hasNext()){
           String key= (String) it.next();
           String[] values = params.get(key);
           values[0] = values[0].trim();
           params.put(key, values);
	     }
    }
    
    @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)});
            }
        }
    }
}

 

3.web.xml配置

3.1 基于spring 配置

<filter>
	<filter-name>sessionFilter</filter-name>
	<filter-class>com.cnpc.oms.common.service.SessionFilter</filter-class>
</filter>
<filter-mapping>
	<filter-name>sessionFilter</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>

 3.2基于javax.serlvet.Filter

 <filter>
	<filter-name>commonFilter</filter-name>
	<filter-class>com.cnpc.oms.common.service.CommonFilter</filter-class>
</filter>
<filter-mapping>
	<filter-name>commonFilter</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>

    

参考文章：http://blog.csdn.net/xieyuooo/article/details/8447301

 

 

评论

3 楼 machao299 2016-11-15  

楼主你好，现在测试发现有个问题，modifyParameterValues 已经被执行，但去空格后的内容没有回写到requerst里，程序里获取的字段依然是带空格的内容。
        this.params.putAll(request.getParameterMap()); 
        this.modifyParameterValues();

第17行取出所有parameter 放在了第10行的 private Map<String , String[]> params = new HashMap<String, String[]>(); 里， 然后modifyParameterValues做空格处理， 没看见你回写parameter 是不是应该有个和this.params.putAll(request.getParameterMap());   对应的回写动作？

2 楼 沉默的水 2016-07-28  

貌似所有的jsp：include通过jsp:param传进去的参数都变null了

1 楼 superscorpio 2013-05-16  

modifyParameterValues里获取的String数组可能是null吧 。

包结构都搞出来了。