实现思路：通过过滤器对jsp页面进行拦截，对出现的敏感文字进行替换，然后替换后的内容再输出到jsp页面，敏感文字替换内容从proppreties配置文件中读取（内容过多的话也可从数据库中读取）。
首先建一个servlet过滤器类，在web.xml配置好过滤器：
<filter>
<filter-name>TextFilter</filter-name>
<filter-class>cn.servlet.filter.TextFilter</filter-class>
<init-param>
<param-name>file</param-name>
<param-value>/WEB-INF/textfilter.properties</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>TextFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
在过滤器类中读取配置和proppreties文件
过滤器类代码：
public class TextFilter implements Filter {
private FilterConfig config;
private Properties pp=new Properties();
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
// TODO Auto-generated method stub
//自定义response
HttpCharacterResponseWapper response=new HttpCharacterResponseWapper((HttpServletResponse)res);
//System.out.println("character");
//提交给servlet
chain.doFilter(req, response);
//得到缓存在自定义response中的输出内容
String output=response.getCharArrayWriter().toString();
//修改，替换
for(Object obj:pp.keySet()){
String key=(String)obj;
output=output.replace(key, pp.getProperty(key));
}
//输出
PrintWriter out=res.getWriter();
out.write(output);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
config=filterConfig;
String file=config.getInitParameter("file");
//或者绝对路径
String realpath=config.getServletContext().getRealPath(file);
try {
pp.load(new FileInputStream(realpath));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
doFilter方法中的HttpCharacterResponseWapper 是自定义的response，HttpCharacterResponseWapper 类如下：
public class HttpCharacterResponseWapper extends HttpServletResponseWrapper {
private CharArrayWriter charArrayWriter=new CharArrayWriter();
public HttpCharacterResponseWapper(HttpServletResponse response) {
super(response);
// TODO Auto-generated constructor stub
}
@Override
public PrintWriter getWriter() throws IOException {
// TODO Auto-generated method stub
return new PrintWriter(charArrayWriter);
}
public CharArrayWriter getCharArrayWriter() {
return charArrayWriter;
}
}
这里需要定义一个CharArrayWriter 字符输出流对jsp内容进行包装，相当于缓存流，不然代码执行chain.doFilter(req, response)后就直接到下一个filter或jsp页面，无法获取到jsp内容，所以需要自定义一个waapper对jsp内容进行缓存，才能对其进行替换；替换完通过out输出到页面。