[原创]过滤器过滤特殊符号

首先，列出我用到的参考资料吧：

资料一来自：http://magicgod.javaeye.com/blog/146537

资料二来自：http://blog.sina.com.cn/s/blog_56000153010005iq.html

我就是根据上面的两个资料，写了一个FILTER和一个JAVA 类，具体如下：

FILTER: SpecialCharacterFilter

import java.io.IOException;

import java.util.Enumeration;

import java.util.HashMap;



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.HttpServlet;

import javax.servlet.http.HttpServletRequest;





public class SpecialCharacterFilter extends HttpServlet implements Filter {



	protected FilterConfig config;



	public void destroy() {

	}



	public void doFilter(ServletRequest req, ServletResponse res,

			FilterChain chain) throws IOException, ServletException {

		System.out.println("[SpecialCharacterFilter] : doFilter *************");

		HttpServletRequest request = (HttpServletRequest)req;

		HashMap m = new HashMap(request.getParameterMap());

		HashMap mm = new HashMap();

		Enumeration enu = request.getParameterNames();

		if(m.size() > 0 && processParameters(m, enu, mm)) {

			ParameterRequestWrapper wrapRequest = new ParameterRequestWrapper(request, mm);

			chain.doFilter(wrapRequest, res);

		} else {

			chain.doFilter(req, res);

		}

	}



	public void init(FilterConfig arg0) throws ServletException {

		this.config = arg0;

	}



	public boolean processParameters(HashMap m, Enumeration enu, HashMap mm) {

		System.out.println("[SpecialCharacterFilter] : processParameters *************");

		if (m != null && enu != null) {

			while (enu.hasMoreElements()) {

				String key = (String)enu.nextElement();

				String [] values = (String [])m.get(key); 

				for(int i = 0; i < values.length; i ++) {

					if (values[i] != null) {

						values[i] = values[i].trim();

						values[i] = values[i].replaceAll("&", "&");

						values[i] = values[i].replaceAll("<", "<");

						values[i] = values[i].replaceAll(">", ">");

						values[i] = values[i].replaceAll("/t", "    ");

						values[i] = values[i].replaceAll("/r/n", "/n");

						values[i] = values[i].replaceAll("/n", "
");

						values[i] = values[i].replaceAll("  ", "  ");

						values[i] = values[i].replaceAll("'", "'");

						values[i] = values[i].replaceAll("////", "/");

					}

				}

				mm.put(key, values);

			}

		}

		return true;

	}



}

JAVA 类：ParameterRequestWrapper 

import java.util.Enumeration;

import java.util.Map;

import java.util.Vector;



import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;



public class ParameterRequestWrapper extends HttpServletRequestWrapper {



	private Map params;



	public ParameterRequestWrapper(HttpServletRequest request, Map newParams) {

		super(request);

		this.params = newParams;

	}



	public Map getParameterMap() {

		return params;

	}



	public Enumeration getParameterNames() {

		Vector l = new Vector(params.keySet());

		return l.elements();

	}



	public String[] getParameterValues(String name) {

		Object v = params.get(name);

		if (v == null) {

			return null;

		} else if (v instanceof String[]) {

			return (String[]) v;

		} else if (v instanceof String) {

			return new String[] { (String) v };

		} else {

			return new String[] { v.toString() };

		}

	}



	public String getParameter(String name) {

		Object v = params.get(name);

		if (v == null) {

			return null;

		} else if (v instanceof String[]) {

			String[] strArr = (String[]) v;

			if (strArr.length > 0) {

				return strArr[0];

			} else {

				return null;

			}

		} else if (v instanceof String) {

			return (String) v;

		} else {

			return v.toString();

		}

	}

}

最后，还是写一下WEB.XML的配置吧：

	

		specialCharacterFilter

		

			com.fhn.vismp.common.SpecialCharacterFilter

		

	



	

		specialCharacterFilter

		*.do

	

	

		specialCharacterFilter

		*.jsp