javaweb中的乱码问题大集合
浏览数：11 /
时间：2015年06月09日
package com.itheima.response;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//使用字节流输出中文内容
public class ResponseDemo1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
test2(response);
}
//服务器端 UTF-8
private void test2(HttpServletResponse response) throws IOException {
String data = "您吃了吗";
byte [] b = data.getBytes("UTF-8");
//服务器端 UTF-8
//通知浏览器，查UTF-8码表
，下面 三句话等效，写任意一句都对。
//response.getOutputStream().write("<meta http-equiv=‘Content-Type‘ content=‘text/html;charset=UTF-8‘>".getBytes());
//response.setHeader("Content-Type", "text/html;charset=UTF-8");
response.setContentType("text/html;charset=UTF-8");
response.getOutputStream().write(b);
}
//服务器端和客户端都使用本地默认的编码GBK：没有乱码
private void test1(HttpServletResponse response) throws IOException {
String data = "您吃了吗";
byte [] b = data.getBytes();//查GBK（本地默认的）
response.getOutputStream().write(b);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2.用字符流输出中文，1是字节流输出中文
package com.itheima.response;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//用字符流输出中文
public class ResponseDemo2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String data = "还没有吃吃吃吃吃吃";
// response.setCharacterEncoding("UTF-8");//该字符流默认的编码为UTF-8
// response.setContentType("text/html;charset=UTF-8");//通知浏览器使用UTF-8
//下面一句相当于上面的两句
response.setContentType("text/html;charset=UTF-8");//不仅能通知浏览器使用UTF-8，而且还会改字符流的编码为UTF-8
PrintWriter pw = response.getWriter();//在Servlet中，协议规定使用ISO-8859-1
pw.write(data);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
上面两个程序都是输出数据，以下是从表单(区别get和post两种方式，post方式处理起来比较简单)中获取中文数据，如何防止乱码呢？请看下面。。。
3.常用表单输入域的值获取
package com.itheima.request;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.beanutils.BeanUtils;
import com.itheima.domain.Student;
//常用表单输入域的值获取
public class RequestDemo5 extends HttpServlet {
//GET请求方式的参数编码
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String name = request.getParameter("name");//码编错了
//取到你传给我的字节序列
byte b[] = name.getBytes("ISO-8859-1");
//重新编码
System.out.println(new String(b,"UTF-8"));
}
//POST请求方式的数据编码：建议使用
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");//只对POST请求方式有效
Student s = new Student();
try {
BeanUtils.populate(s, request.getParameterMap());//发生类型的自动转换，但仅限基本数据类型
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(s);
}
}
private void testDemo1(HttpServletRequest request)
throws UnsupportedEncodingException {
request.setCharacterEncoding("UTF-8");
//response.setContentType("text/html;charset=UTF-8");//把得到的数据给浏览器的话，就要加上这句。如果是在控制台输出，就不需要加这句。
String username = request.getParameter("username");
System.out.println(username);
// response.getWriter().write(username);
}
4,分清请求编码和响应输出的编码，两者并没有关系
package com.itheima.request;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//分清请求编码和响应输出的编码，两者并没有关系
public class RequestDemo6 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//接收数据：请求
request.setCharacterEncoding("UTF-8");
String name = request.getParameter("name");
//----------------------------------------------------
//响应数据：响应
response.setContentType("text/html;charset=GBK");
response.getWriter().write(name);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
5.把表单中的数据封装到JavaBean，输入中文，也不报错。请看下面。。。
package com.itheima.request;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.beanutils.BeanUtils;
import com.itheima.domain.User2;
public class RequestDemo0 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
User2 user = new User2();
request.setCharacterEncoding("UTF-8");
System.out.println("封装前"+user.toString());
Map<String, String[]> map = request.getParameterMap();
response.setContentType("text/html;charset=UTF-8");
try {
BeanUtils.populate(user, map);
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("封装后"+user.toString());
response.getWriter().write(user.toString());
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
JavaBean：
package com.itheima.domain;
import java.util.Arrays;
public class User2 {
private String username;
private String[] password;
private String code;
@Override
public String toString() {
return "User2 [username=" + username + ", password="
+ Arrays.toString(password) + ", code=" + code + "]";
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String[] getPassword() {
return password;
}
public void setPassword(String[] password) {
this.password = password;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
}
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