package com.yiboit.hhs.filter;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;

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 CharsetFilter implements Filter {
	/** 保存用戶指定編碼 */
	protected String encoding = null;

	/**
	 * 初始化過濾器方法，由系統創建Filter時自動調用 把web.xml中用戶指定的編碼保存在本類的屬性中
	 */
	public void init(FilterConfig filterConfig) throws ServletException {
		this.encoding = filterConfig.getInitParameter("encoding");
	}

	/**
	 * 執行過濾功能 將參數信息按指定的編碼進行轉換
	 */
	public void doFilter(ServletRequest req, ServletResponse res,
			FilterChain chain) throws IOException, ServletException {

		Map parameterMap = req.getParameterMap();

		if (!parameterMap.isEmpty()) {
			Iterator it = parameterMap.keySet().iterator();
			String value[] = null;
			while (it.hasNext()) {
				value = (String[]) parameterMap.get(it.next());

				for (int i = 0; i < value.length; i++) {
					value[i] = new String(value[i].getBytes("ISO-8859-1"),
							encoding);
				}
			}
		}

		chain.doFilter(req, res);
	}

	/**
	 * 銷毀方法，在系統銷毀Filter之前由系統自動調用
	 */
	public void destroy() {
		this.encoding = null;
	}
}