非法字符过滤 HttpServletResponse

在页面显示前对将页面非法符过滤掉


IllegalCharacterFilter.java

package *;

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

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 javax.servlet.http.HttpServletResponseWrapper;

import *.IllegalWordUtil;

public class IllegalCharacterFilter implements Filter {
	
	@Override
	public void destroy() {
		// TODO Auto-generated method stub

	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		   HttpServletRequest servletrequest = (HttpServletRequest) request;
		   HttpServletResponse servletresponse = (HttpServletResponse) response;
		   request.setCharacterEncoding("utf-8");
	       response.setCharacterEncoding("utf-8");
		   WrapperImpl wrapper = new WrapperImpl(servletresponse);
           chain.doFilter(request, wrapper);
           PrintWriter out = response.getWriter();
           out.println(IllegalWordUtil.filterIllegalWords(wrapper.toString()));
	}

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

	
	private class WrapperImpl extends HttpServletResponseWrapper {
        private CharArrayWriter output;

        public WrapperImpl(HttpServletResponse response) {
            super(response);
            output = new CharArrayWriter();
        }

        public String toString() {
            return output.toString();
        }

        public PrintWriter getWriter() {
            return new PrintWriter(output);
        }
    }
}

IllegalWordUtil.java

package *;

import java.io.IOException;
import java.util.Properties;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class IllegalWordUtil{
	protected static final Logger logger = LoggerFactory.getLogger(IllegalWordUtil.class);
	
	private final static String pattern;
	private final static String replacement;
	private final static String illegalWords;
	private final static String illegalWordRegx;
	private static Pattern patterns = null;
	static{
		Properties properties = new Properties();  
		try{
			properties.load(IllegalWordUtil.class.getResourceAsStream("/illegal.keywords.properties"));//加载非法关键字资源文件
		}catch(IOException ioe){
			ioe.printStackTrace();
			logger.error("Cound not load illegal.keywords.properties");
			throw new RuntimeException("Cound not load illegal.keywords.properties");
		}
		//取出所有非法关键字
		illegalWords = properties.getProperty("words", "");
                //以，为分格符取出每个非法关键字
		pattern = properties.getProperty("pattern", ",");
                //将非法字符替换成***
		replacement = properties.getProperty("replacerex", "***");;
		illegalWordRegx = "(" + illegalWords.trim().replaceAll(pattern, "|") + ")";
		patterns = Pattern.compile(new String(illegalWordRegx.toString()));
	}
	
	public static String filterIllegalWords(String sentence) {
		Matcher m = patterns.matcher(sentence);
		return m.replaceAll(replacement);
	}

	public static boolean isIllegalWord(String word) {
		Matcher m = patterns.matcher(word);
		return m.find(0);
	}
	

}

web.xml

<filter>
      <filter-name>IllegalCharacterFilter</filter-name>
      <filter-class>desirelist.web.servlet.IllegalCharacterFilter</filter-class>
</filter>
<filter-mapping>
    	<filter-name>UrlRewriteFilter</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>