setcharacterencodingfilter.java

java + sqlserver2000编写的一个网上购书系统,实现了一些基本的功能,但对于初学者来说这个系统已经足以起到帮助作用

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 {
	protected String encoding = null;
	protected FilterConfig filterConfig = null;
	protected boolean ignore = true;

	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=true;
		else if(value.equalsIgnoreCase("true"))
			this.ignore=true;
		else
			this.ignore=false;
	}

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {//TODO 自动生成方法存根
		if (ignore || (request.getCharacterEncoding() == null)) {
			String encoding = selectEncoding(request);
			if (encoding != null)
				request.setCharacterEncoding(encoding);
		}
		chain.doFilter(request, response);
	}

	public static void main(String args[])
	{
		
	}
	
	
	public void destroy() {//TODO 自动生成方法存根
		this.encoding = null;
		this.filterConfig = null;
	}

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