解决GET方式请求中文乱码的几种方法

大概内容：
1.直接在目标servlet中编码参数
2.过滤器解决中文乱码
3.通过一个基类servlet解决中文乱码

直接在目标servlet中编码参数

直接上代码：

import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@SuppressWarnings("serial")public class Demo3Servlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        //这里设置输出到前端的文本的编码方式        response.setContentType("text/html;charset=utf-8");        String name=request.getParameter("name");        String age=request.getParameter("age");        //手动将参数值编码        name=new String(name.getBytes("iso-8859-1"),"utf-8");        //控制台输出        System.out.println(name+","+age);        //网页上输出        response.getWriter().print(name+":欢迎光临");    }    //这里该方法没有实际用到    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        String name=request.getParameter("name");        String age=request.getParameter("age");        System.out.println(name=","+age);        response.getWriter().print(name+":欢迎光临");    }}

通过过滤器解决中文乱码

1.先写一个过滤器：

import java.io.IOException;import java.io.UnsupportedEncodingException;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;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;public class CharacterFilter implements Filter{    @Override    public void destroy() {    }    @Override    public void doFilter(ServletRequest request, ServletResponse response,            FilterChain chain) throws IOException, ServletException {        HttpServletRequest httpRequest=(HttpServletRequest) request;        //生成我们自己包装好的类        MyRequest req=new MyRequest(httpRequest);        chain.doFilter(req, response);//放行    }    @Override    public void init(FilterConfig filterConfig) throws ServletException {        System.out.println("过滤器初始化了!");    }}/* * 装饰类 * 解决get方式请求中的中文乱码 */class MyRequest extends HttpServletRequestWrapper{    public MyRequest(HttpServletRequest request) {        super(request);    }    //修改增强getParameter方法    @Override    public String getParameter(String name) {        //先获取原来参数的值        String value=super.getParameter(name);        if("get".equalsIgnoreCase(super.getMethod())){//判断是否是"get"方式请求            try {                //我们自己编码前端传来的参数                value=new String(value.getBytes("iso-8859-1"),"utf-8");            } catch (UnsupportedEncodingException e) {                e.printStackTrace();            }        }        //返回我们处理过的参数值        return value;    }    //修改增强getParameterValues方法    @Override    public String[] getParameterValues(String name) {        //获取原来的参数值        String values[]=super.getParameterValues(name);        if("get".equalsIgnoreCase(super.getMethod())){//判断是否是"get"方式             for(int i=0;i<values.length;i++){                try {                    //我们自己编码前端传过来的参数，其中getCharacterEncoding()是我们在servlet中自己设置的编码，也可以直接写哪种编码                    values[i]=new String(values[i].getBytes("ISO-8859-1"),getCharacterEncoding());                } catch (UnsupportedEncodingException e) {                    e.printStackTrace();                }            }        }        //返回处理过的参数数组        return values;    }    ////修改增强getParameterMap方法    @Override    public Map<String, String[]> getParameterMap() {        //获取原来的参数值        Map<String, String[]> map=super.getParameterMap();        if("get".equalsIgnoreCase(super.getMethod())){//判断是否是"get"方式            Iterator<Map.Entry<String, String[]>> it=map.entrySet().iterator();            while(it.hasNext()){                String values[]=it.next().getValue();                for(int i=0;i<values.length;i++){                    try {                        values[i]=new String(values[i].getBytes("ISO-8859-1"),getCharacterEncoding());                    } catch (UnsupportedEncodingException e) {                        e.printStackTrace();                    }                }            }        }        //返回处理过的map        return map ;    }}

2.写一个处理数据的servlet

import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@SuppressWarnings("serial")public class Demo1Servlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        //这里给过滤器的装饰类提前设置好编码        request.setCharacterEncoding("utf-8");        //这里设置编码是输出到前端时保证编码不出错        response.setContentType("text/html;charset=utf-8");        String name=request.getParameter("name");        String strAge=request.getParameter("age");        //输出到控制台        System.out.println(name+","+strAge);        //输出到页面        response.getWriter().print(name+":欢迎光临");    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        //因为这里演示get方式请求，所以直接调用doGet()方法        doGet(request, response);    }}

通过一个基类servlet解决中文乱码

1.先写一个BaseServlet类

import java.io.IOException;import java.io.UnsupportedEncodingException;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.Iterator;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;import javax.servlet.http.HttpServletResponse;@SuppressWarnings("serial")public abstract class BaseServlet extends HttpServlet{    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        String cmd=req.getParameter("cmd");        if(null==cmd || cmd.equals("")){            cmd="execute";        }        try {            Method method=this.getClass().getMethod(cmd, HttpServletRequest.class, HttpServletResponse.class);            //声明我们自己的包装类            MyRequest myRequest=new MyRequest(req);            method.invoke(this, myRequest, resp);        } catch (NoSuchMethodException e) {            e.printStackTrace();        } catch (SecurityException e) {            e.printStackTrace();        } catch (IllegalAccessException e) {            e.printStackTrace();        } catch (IllegalArgumentException e) {            e.printStackTrace();        } catch (InvocationTargetException e) {            e.printStackTrace();        }    }    @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        doGet(req, resp);    }    public abstract void execute(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException;}/* * 装饰类 * 解决get方式请求中的中文乱码 */class MyRequest extends HttpServletRequestWrapper{    public MyRequest(HttpServletRequest request) {        super(request);    }    //修改增强getParameter方法    @Override    public String getParameter(String name) {        //先获取原来参数的值        String value=super.getParameter(name);        if("get".equalsIgnoreCase(super.getMethod())){//判断是否是"get"方式请求            try {                //我们自己编码前端传过来的参数，其中getCharacterEncoding()是我们在servlet中自己设置的编码，也可以直接写哪种编码                value=new String(value.getBytes("ISO-8859-1"),getCharacterEncoding());            } catch (UnsupportedEncodingException e) {                e.printStackTrace();            }        }        //返回我们处理过的参数值        return value;    }    //修改增强getParameterValues方法    @Override    public String[] getParameterValues(String name) {        //获取原来的参数值        String values[]=super.getParameterValues(name);        if("get".equalsIgnoreCase(super.getMethod())){//判断是否是"get"方式             for(int i=0;i<values.length;i++){                try {                    //我们自己编码前端传过来的参数                    values[i]=new String(values[i].getBytes("ISO-8859-1"),getCharacterEncoding());                } catch (UnsupportedEncodingException e) {                    e.printStackTrace();                }            }        }        //返回处理过的参数数组        return values;    }    ////修改增强getParameterMap方法    @Override    public Map<String, String[]> getParameterMap() {        //获取原来的参数值        Map<String, String[]> map=super.getParameterMap();        if("get".equalsIgnoreCase(super.getMethod())){//判断是否是"get"方式            Iterator<Map.Entry<String, String[]>> it=map.entrySet().iterator();            while(it.hasNext()){                String values[]=it.next().getValue();                for(int i=0;i<values.length;i++){                    try {                        values[i]=new String(values[i].getBytes("ISO-8859-1"),getCharacterEncoding());                    } catch (UnsupportedEncodingException e) {                        e.printStackTrace();                    }                }            }        }        //返回处理过的map        return map ;    }}

2.写一个处理数据的servlet

import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.hncu.utils.BaseServlet;@SuppressWarnings("serial")//这里要继承我们自己写的BaseServlet类，并实现他的抽象方法public class Demo2Servlet extends BaseServlet{    @Override    //重写父类的抽象方法    public void execute(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        //这里给过滤器的装饰类提前设置好        req.setCharacterEncoding("utf-8");        //这里设置编码是输出到前端时保证编码不出错        resp.setContentType("text/html;charset=utf-8");        String name=req.getParameter("name");        String age=req.getParameter("age");        System.out.println(name+","+age);        resp.getWriter().print(name+":欢迎光临!");    }}

上述的三种方式都可以解决get方式请求的中文乱码问题，第一种最简单，第二种和第三种其实原理是差不多的：都是对HttpServletRequest进行包装，修改或者增强其中的一些方法；下面贴上主页代码和web.xml配置文件的代码：
index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>解决get方式请求中文乱码的两种方式演示</title>  </head>  <body>    <h3>过滤器解决中文乱码</h3>    <a href="Demo1Servlet?name=叶秋&age=21">过滤器解决中文乱码</a><br/>    <a href="Demo2Servlet?name=黄少天&age=22">基类serlvet解决中文乱码</a><br/>    <a href="Demo3Servlet?name=苏沐橙&age=23">直接在servlet中解决乱码</a><br/>  </body></html>

web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0"     xmlns="http://java.sun.com/xml/ns/javaee"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  <display-name></display-name>  <!-- 配置过滤器 -->  <filter>    <filter-name>demo1</filter-name>    <filter-class>cn.hncu.filter.CharacterFilter</filter-class>  </filter>  <filter-mapping>    <filter-name>demo1</filter-name>    <servlet-name>Demo1Servlet</servlet-name>  </filter-mapping>  <!-- 配置servlet -->  <servlet>    <servlet-name>Demo1Servlet</servlet-name>    <servlet-class>cn.hncu.servlet.Demo1Servlet</servlet-class>  </servlet>  <servlet>    <servlet-name>Demo2Servlet</servlet-name>    <servlet-class>cn.hncu.servlet.Demo2Servlet</servlet-class>  </servlet>  <servlet>    <servlet-name>Demo3Servlet</servlet-name>    <servlet-class>cn.hncu.servlet.Demo3Servlet</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>Demo1Servlet</servlet-name>    <url-pattern>/Demo1Servlet</url-pattern>  </servlet-mapping>      <servlet-mapping>    <servlet-name>Demo2Servlet</servlet-name>    <url-pattern>/Demo2Servlet</url-pattern>  </servlet-mapping>  <servlet-mapping>    <servlet-name>Demo3Servlet</servlet-name>    <url-pattern>/Demo3Servlet</url-pattern>  </servlet-mapping>      <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>