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

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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<String, String[]> m = new HashMap(request.getParameterMap());

HashMap<String, String[]> mm = new HashMap<String, String[]>();

Enumeration<String> 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<String, String[]> m, Enumeration enu, HashMap<String, String[]> 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", "<br>");

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

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

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

}

}

mm.put(key, values);

}

}

return true;

}



}


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<String, String[]> m = new HashMap(request.getParameterMap());

HashMap<String, String[]> mm = new HashMap<String, String[]>();

Enumeration<String> 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<String, String[]> m, Enumeration enu, HashMap<String, String[]> 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", "<br>");

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

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

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

}

}

mm.put(key, values);

}

}

return true;

}



}
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JAVA 类：ParameterRequestWrapper

JAVA 类：ParameterRequestWrapper view plaincopy to clipboardprint?
<PRE class=java name="code">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();

}

}

}
</PRE>
<PRE class=java name="code">最后，还是写一下WEB.XML的配置吧：</PRE>
<PRE class=java name="code"><PRE class=xml name="code"> <filter>

<filter-name>specialCharacterFilter</filter-name>

<filter-class>

com.fhn.vismp.common.SpecialCharacterFilter

</filter-class>

</filter>



<filter-mapping>

<filter-name>specialCharacterFilter</filter-name>

<url-pattern>*.do</url-pattern>

</filter-mapping>

<filter-mapping>

<filter-name>specialCharacterFilter</filter-name>

<url-pattern>*.jsp</url-pattern>

</filter-mapping></PRE>

</PRE>