request对象和response对象(3)

p>        response.setCharacterEncoding("UTF-8");

p>        response.setContentType("text/html;charset=UTF-8");

p>        PrintWriter out = response.getWriter();

p>        out.write(s);

p>    }

p>    //字符流输出中文数据

p>    private void test3(HttpServletResponse response) throws IOException{

p>        String s = "你好！三";

p>        response.setContentType("text/html;charset=UTF-8");

p>        PrintWriter out = response.getWriter();

p>        out.write(s);

p>    }

p> 

p>    

p>    public void doPost(HttpServletRequest request, HttpServletResponse response)

p>            throws ServletException, IOException {

p>        doGet(request,response);

p>    }

p>}

p>复制代码

p>分析：

p> 

p>乱码原因：以默认编码发送数据 ISO-8859-1（没有中国二字编码），此时会发生乱码

p> 

p>解决办法：

p> 

p>1）

p> 

p>setCharacterEncoding(“UTF-8”);//更改编码为UTF-8

p> 

p>response.setHead(“Context-type”,”text/html;charset=UTF-8”);//告诉客户端编码方式

p> 

p>2）response.setContentType("text/html;charset=utf-8");

p> 

p>在字符流输出中文数据时:

p> 

p>response.setContentType("text/html;charset=utf-8");有两个作用：

p> 

p>通知字符流以UTF-8编码输出

p> 

p>通知客户端以UTF-8解码显示

p> 

p>3.输出随机验证码

p> 

p>复制代码

p>package cn.lsl.response;

p> 

p>import java.awt.Color;

p>import java.awt.Font;

p>import java.awt.Graphics;

p>import java.awt.image.BufferedImage;

p>import java.io.IOException;

p>import java.util.Random;

p>import javax.imageio.ImageIO;

p>import javax.servlet.ServletException;

p>import javax.servlet.http.HttpServlet;

p>import javax.servlet.http.HttpServletRequest;

p>import javax.servlet.http.HttpServletResponse;

p> 

p>public class ResponseDemo3 extends HttpServlet {

p> 

p>    public void doGet(HttpServletRequest request, HttpServletResponse response)

p>            throws ServletException, IOException {

p>        //通知浏览器不要缓存

p>        response.setHeader("Expires", "-1");

p>        response.setHeader("Cache-Control", "no-cache");

p>        response.setHeader("Pragma", "no-cache");

p>        

p>        int width = 120;

p>        int height = 25;

p>        //创建一副内存图像BufferedImage