对字符编码的‘过滤’
web.xml的配置：
==============================================
<filter>
<filter-name>charsetClass</filter-name>
<filter-class>CharsetFilter</filter-class>
<init-param>
<param-name>enable</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>charset</param-name>
<param-value>gb18030</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>charsetClass</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
=============================================
java类：
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;
public class CharsetFilter implements Filter{
private String charset;
private boolean enable = false;
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if(enable){
request.setCharacterEncoding(charset);
}
chain.doFilter(request, response);
}
public void init(FilterConfig config) throws ServletException {
if(config.getInitParameter("enable").equals("true")){
enable = true;
}
charset = config.getInitParameter("charset");
}
}
说明：Filter最大的用途就是字符编码的统一转换 和 权限的验证
权限验证，Filter类则这样写：
public class holdOnAdminPages implements Filter{
private String user;
private boolean enable = false;
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
chain.doFilter(request, response);
HttpServletRequest req = (HttpServletRequest)request;
HttpServletResponse res = (HttpServletResponse)response;
String uri = req.getRequestURI();
if(!enable){
return;
}
if(uri.indexOf("login.jsp") != -1){
return;
}
if(uri.indexOf("loginHandler.jsp") != -1){
return;
}
if(req.getSession().getAttribute(user) == null){
System.out.println(req.getSession().getAttribute(user));
res.sendRedirect("login.jsp");
}
}
public void init(FilterConfig config) throws ServletException {
if(config.getInitParameter("enable").equals("true")){
enable = true;
}
user = config.getInitParameter("user");
System.out.println(enable);
System.out.println(user);
}
}
其他用法，我就不知道了，等开发中知道了 - zai - 分享吧！