setcharacterencodingfilter.java

简易商品管理系统代码

//设置request编码的filter
package jdbcbook.pub.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;
import javax.servlet.UnavailableException;
/**
 * 设置Tomcat正确编码格式
 */
public class SetCharacterEncodingFilter implements Filter
{
	protected String encoding=null;
	protected FilterConfig filterConfig=null;
	protected boolean ignore=true;
	//设置申请对象值为空,有利于内存的快速释放
	public void destroy()
	{
		this.encoding=null;
		this.filterConfig=null;
	}
	//Filter的主体操作
	public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain) throws IOException,ServletException
	{
		//判断是否需要进行编码的设置
		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);
		}
		//pass control on to the next filter
		chain.doFilter(request,response);
	}
	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("no"))
			this.ignore=true;
		else
			this.ignore=false;
	}
	//得到配置的编码类型
	 protected String selectEncoding(ServletRequest request)
	 {
		 return (this.encoding);
	 }

}