常见乱码与下载图片

 

一、解决中文乱码问题，解决中文乱码问题有三种方法：

1）通过设置响应的头来处理的

response.setHeader("Content-Type","text/.html;charset=UTF-8");

2）通过字节设置响应的头来处理的

response.getOutputStream().write("中国".getBytes("UTF-8"));

3）使用html语言里面的<meta>标签来控制浏览器行为

response.getOutputStream().write("<meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">".getBytes());

二、文件下载

下面是文件下载的代码：

package cn.csdn.web.servlet;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.UnsupportedEncodingException;

import java.net.URLEncoder;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Demo01Servlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

   

   this.doPost(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

 

       /*文件下载

        * 首先知道下载的资源*/

ServletContext context = this.getServletContext();

String path =context.getRealPath("/WEB-INF/classes/res/aa.jpg");

/*构造文件*/

File file= new File(path);

/*构造文件的输入流*/

InputStream is = new FileInputStream(file);

/*写：输出流

 * 文件下载*/

response.setHeader("content-disposition", "attachment;filename=");

OutputStream os   = response.getOutputStream();

byte buffer[] = new byte[1024];

int len = 0;

while((len=is.read(buffer))!=-1){

os.write(buffer,0,len);

}

os.close();

is.close();

     

}

}

如果下载的是中文文件，就把上面代码中的

String path =context.getRealPath("/WEB-INF/classes/res/aa.jpg")

aa.jpg改为汉字

把response.setHeader("content-disposition", "attachment;filename=");

加上URLEncoder.encode(file.getName(), "UTF-8")

如：response.setHeader("content-disposition", "attachment;filename="+URLEncoder.encode(file.getName(), "UTF-8"));