setcharacterencodingfilter.java

一个简单的汽车租赁系统 jsp+struts+oracle

package filter;

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 SetCharacterEncodingFilter implements Filter {
	/*
	 * 设置TOMCAT的正确编码格式
	 * */
   protected String encoding=null;
   protected FilterConfig filterConfig=null;
   protected boolean ignore=true;
   
 //设置申请对象值为空,有利于内存资源的快速释放
	public void destroy() {
	
   this.encoding="utf-8";
   this.filterConfig=null;
	}

	 //filter的主体操作
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {

		//判断是否需要进行的编码设置
		if(ignore||(request.getCharacterEncoding()==null))
		{
			//得到配置文件的编码类型
			String  encoding=selectEncoding(request);
			if(encoding!=null)
			{
				request.setCharacterEncoding(encoding);
				response.setContentType("text/html;charset="+encoding);
			}
		}
		//pass control on to the next filter
		chain.doFilter(request, response);
	}

	//初始化方法,通过配置的参数设置标识变量
	public void init(FilterConfig filterConfig) throws ServletException {
		this.filterConfig=filterConfig;
		this.encoding=filterConfig.getInitParameter("encoding");
		String value=filterConfig.getInitParameter("ignore");
		if(value==null)
			this.ignore=false;
		else
			if(value.equalsIgnoreCase("false"))
				this.ignore=true;
			else
				if(value.equalsIgnoreCase("yes"))
					this.ignore=true;
				else
					this.ignore=false;
	}
	//得到配置文件的编码类型
	protected String selectEncoding(ServletRequest request)
	{
		return(this.encoding);
	}
}