encodingfilter.java

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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 EncodingFilter implements Filter {
	
	public EncodingFilter(){
		System.out.println("过滤器构造函数");
	}
	private String encodingName;
	public void init(FilterConfig fc) throws ServletException {
		//初始化函数，服务器运行能自动运行一次
		System.out.println("过滤器init函数");
		//fc.getServletContext().getInitParameter(arg0)得到全局参数
		encodingName = fc.getInitParameter("encodingName");//得到局部参数
	}
	
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		//每次提交都会运行
		System.out.println("过滤器doFilter函数");
		
		request.setCharacterEncoding(encodingName);//解决中文问题
		//过滤器是在提交到达处理模块之前运行，所以这里要将请求向后传递
		chain.doFilter(request, response);

	}

	public void destroy() {
		//消亡时运行
		System.out.println("过滤器destroy函数");

	}

}