setcharacterencodingfilter.java

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package edu.buptsse.sxjd.common;


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 destroy( ) 
	{
		this.encoding = null;
		this.filterConfig = null;
	}

	public void doFilter( ServletRequest request, 
					ServletResponse response,
					FilterChain chain )
			throws IOException, ServletException 
	{
		// Conditionally select and set the character encoding to be used
		if ( !ignore || (request.getCharacterEncoding() == null) ) 
		{
			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;
	}

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