Javaweb解决全站字符乱码问题（POST和GET）-CFANZ编程社区

乱码问题：

1. 获取请求参数中的乱码问题

POST请求:request.setCharaterEncoding("utf-8")

GET请求:new String(request.getParameter("xxx").getBytes("iso-8859-1"),"utf-8");

2.响应的乱码问题

request.setContextType("text/html;charset=utf-8");

分析:基本上在每个servlet中都需要解决乱码问题，所以应把这个工作放到过滤器中来完成

下面就通过一个案例来解释下如何完成这歌乱码问题

(1)首先创建一个index.jsp

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>//这个需要你自己导jstl-1.2.jar
<!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>
<a href="<c:url value='/AServlet?username=张三'/>">点击这里</a>
<form action="<c:url value='/AServlet'/>" method="post">
用户名:<input type="text" name="username" value="李四"/>
<input type="submit" value="提交"/>
</form>
</body>
</html>

(2)创建一个名叫AServlet的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 AServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      response.setContentType("text/html;charset=utf-8");
      String name = request.getParameter("username");
      response.getWriter().println(name);
  }

  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("text/html;charset=utf-8");
    String name = request.getParameter("username");
    response.getWriter().println(name);
  }

}

(3)点击运行，会出现下面的乱码

Javaweb解决全站字符乱码问题（POST和GET）_html

(4)解决方法

一.创建一个叫EncodingFilter的过滤器，在创建的过程中将pattern中设置为/*这样一来写好的过滤器就可以作用于所有路径下的serlvet，从来代码的可重复性

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;
public class EncodingFilter implements Filter {

  public void destroy() {
  }

  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    //处理post请求编码问题
    request.setCharacterEncoding("utf-8");
    /**
     *处理get请求编码问题
     * 调包request
     * 首先创建一个request的修饰类，然后在放行的时候，使用我们自己的request
     */
    HttpServletRequest req = (HttpServletRequest) request;
    if(req.getMethod().equals("GET")) {
      EncodingRequest er = new EncodingRequest(req);
      chain.doFilter(er, response);
    }else if(req.getMethod().equals("POST")) {
      chain.doFilter(request, response);
    }
  }
  public void init(FilterConfig fConfig) throws ServletException {
  }

}

二.在创建一个EncodingRequest.java

import java.io.UnsupportedEncodingException;

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

public class EncodingRequest extends HttpServletRequestWrapper{
  private HttpServletRequest req;
  public EncodingRequest(HttpServletRequest request) {
    super(request);
    this.req = request;
  }
  /**
   * 这就是需要些的request的装饰类,在EncodingFilter中通过创建EncodingRequest对象来调用getParameter()方法从而解决Get响应出现乱码问题
   */
  public String getParameter(String name) {
    String value = req.getParameter(name);
    try {
      value = new String(value.getBytes("iso-8859-1"), "utf-8");
    } catch (UnsupportedEncodingException e) {
      e.printStackTrace();
    }
    return value;
  }

}