Filter学习

EncodeFilter，实现类如下

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 EncodeFilter implements Filter{
private FilterConfig config=null;
private String encoding = null;

public void destroy() {
this.config = null;
this.encoding = null;
}

public void doFilter(ServletRequest request,
ServletResponse response,
FilterChain chain) throws IOException, ServletException {

String encoding = selectEncoding(request);
if (encoding != null) {
request.setCharacterEncoding(encoding);
}
chain.doFilter(request, response);

}

public void init(FilterConfig config) throws ServletException {
this.config = config;
this.encoding = config.getInitParameter("encoding");
}

protected String selectEncoding(ServletRequest request) {
return (this.encoding);
}

}


Web.xml配置如下，直接访问.jsp或者.do文件，即可进行编码转换
<filter>
<filter-name>Encoding</filter-name>
<filter-class>pocketbook.filterTest.EncodeFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>Encoding</filter-name>
<servlet-name>action</servlet-name>
</filter-mapping>
<filter-mapping>
<filter-name>Encoding</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>

<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>