Filter 解决全站中文乱码问题

最新推荐文章于 2022-03-09 14:27:13 发布

原创最新推荐文章于 2022-03-09 14:27:13 发布 · 703 阅读

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本文详细解读了如何通过过滤器确保全站编码统一，具体介绍了字符编码过滤器的作用、实现原理及关键步骤，包括请求编码设置、响应编码设置以及如何将增强的请求对象传递给Servlet层，确保Web应用中数据传输的一致性和正确性。

/*----------------------Demo1.jsp-----------------------------------------------------------------------------------------------*/

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>


<title>Insert title here</title>
</head>
<body>
	能别报错嘛!!?
	<form action="${pageContext.request.contextPath }/servlet/ServletDemo1" method="post">
		<input type="text" name="username">
		<input type="submit" value="提交">
	</form>
	
</body>
</html>

/*----------------------------------servlet----------------------------------------------------------------------------------------*/

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ServletDemo1 extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		System.out.println(request.getParameter("username"));
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doGet(request, response);
	}

}

/*---------------------------------过滤器----------------------------------------------------------------------------------------*/

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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//解决全站编码统一问题
//请求编码，响应编码
public class CharacterEncodingFilter implements Filter {

	private FilterConfig filterConfig;
	private String defaultEncoding = "utf-8";
	
	public void destroy() {

	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		
		//用户请求至浏览器，请求是带HTTP协议，需要强转
		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse res =  (HttpServletResponse) response;
		//获取XML里的配置信息编码
		String encode = filterConfig.getInitParameter("encodeing");
		//判断配置文件里是否有配置,没有的话就把默认定义的编码指定给encode
		if(encode==null)
			encode = defaultEncoding;
		//设置
		request.setCharacterEncoding(encode); 
		response.setContentType("text/html;charset="+encode);
		//把增强的request传给servlet层
		MyRequest myreq = new MyRequest(req);
		chain.doFilter(myreq, response);
		//chain.doFilter(new MyRequest(req), res);//简写
		
	}

	public void init(FilterConfig filterConfig) throws ServletException {
		this.filterConfig = filterConfig;
	}

}

/*---------------------------------增强request----------------------------------------------------------------------------------------*/

import java.io.UnsupportedEncodingException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class MyRequest extends HttpServletRequestWrapper {

	private HttpServletRequest request;

	public MyRequest(HttpServletRequest request) {
		super(request);
		this.request = request;
	}
	
	public String getParameter(String name){
		//获取用户提交的数据
		String value = request.getParameter(name);
		//判断是否为空
		if( value==null )
			return value;
		
		try {//判断是否为GET提交方式
			if(request.getMethod().equalsIgnoreCase("get")){
				value = new String(value.getBytes("ISO-8859-1"),request.getCharacterEncoding());
			}
			return value;
		} catch (UnsupportedEncodingException e) {
			throw new RuntimeException();
		}
		
	}
	
}