HTTP Servlet Response文件下载基本代码(页码SR3)

素颜马尾好姑娘i 2023-07-07 11:19 15阅读 0赞

![在这里插入图片描述][20200222212659138.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70]  
前端代码

<!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    	<h1>使用a标签直接指向服务器上的资源</h1>
    	<a href="/WEB14/花纹库/龙角.jpg">龙角.jpg</a><br>
    	<a href="/WEB14/花纹库/图腾.jpg">图腾.jpg</a><br>
    	<h1>使用服务器端编码的方式实现文件下载</h1>
    	<a href="/WEB14/download?filename=龙角.jpg">龙角.jpg</a><br>
    	<a href="/WEB14/download?filename=图腾.jpg">图腾.jpg</a><br>
    </body>
    </html>

服务器端代码

package cn.aynortechnology.content;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.InputStream;
    
    import javax.servlet.ServletException;
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class DownloadServlet extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		//获得要下载的文件的名称
    		String filename = request.getParameter("filename");
    		//要下载的这个文件的类型---客户端通过文件的MIME类型取区分类型
    		response.setContentType(this.getServletContext().getMimeType(filename));
    		//告诉客户端该文件不是直接解析而是以附件形式打开(下载)
    		response.setHeader("Content-Disposition", "attachment;filename="+filename);
    		//获取文件的绝对路径
    		String path = this.getServletContext().getRealPath("花纹库/"+filename);
    		//获得该文件的输入流
    		InputStream in = new FileInputStream(path);
    		//获得输出流---通过response获得的输出流 用于向客户端写内容
    		ServletOutputStream out = response.getOutputStream();
    		//文件拷贝的模板代码
    		int len = 0;
    		byte[] buffer = new byte[1024];
    		while((len=in.read(buffer))>0) {
    			out.write(buffer, 0, len);
    		}
    		in.close();
    		out.close();
    	}
    
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    }

![在这里插入图片描述][20200223024128787.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][20200223034418167.png]  
自适应浏览器下载中文文件名文件

package cn.aynortechnology.content;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.URLEncoder;
    
    import javax.servlet.ServletException;
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import sun.misc.BASE64Encoder;
    
    public class DownloadServlet2 extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		//*************文件名称是中文的下载**************//
    		
    		//获得要下载的文件的名称
    		String filename = request.getParameter("filename");
    		//解决获得中文参数的乱码
    		//filename = new String(filename.getBytes("ISO8859-1"),"UTF-8");
    		filename = new String(filename.getBytes("ISO8859-1"),"UTF-8");
    		//获得请求头中的User-Agent
    		String agent = request.getHeader("User-Agent");
    		//根据不同的客户端进行不同的编码
    		if(agent.contains("MSIE")) {
    			//IE浏览器
    			filename = URLEncoder.encode(filename,"utf-8");
    			filename = filename.replace("+", " ");
    		}else if(agent.contains("Firefox")){
    			//火狐浏览器
    			BASE64Encoder base64Encoder = new BASE64Encoder();
    			filename = "=?utf-8?B?"+base64Encoder.encode(filename.getBytes("utf-8"))+"?=";
    		}else {
    			//其他浏览器
    			filename = URLEncoder.encode(filename, "utf-8");
    		}
    		
    		//要下载的这个文件的类型---客户端通过文件的MIME类型取区分类型
    		response.setContentType(this.getServletContext().getMimeType(filename));
    		//告诉客户端该文件不是直接解析而是以附件形式打开(下载)
    		response.setHeader("Content-Disposition", "attachment;filename="+filename);
    		//获取文件的绝对路径
    		String path = this.getServletContext().getRealPath("花纹库/"+filename);
    		//获得该文件的输入流
    		InputStream in = new FileInputStream(path);
    		//获得输出流---通过response获得的输出流 用于向客户端写内容
    		ServletOutputStream out = response.getOutputStream();
    		//文件拷贝的模板代码
    		int len = 0;
    		byte[] buffer = new byte[1024];
    		while((len=in.read(buffer))>0) {
    			out.write(buffer, 0, len);
    		}
    		in.close();
    		out.close();
    	}
    
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    }

[(页码SR1)HTTP Servlet Response设置响应头、重定向、定时刷新][SR1_HTTP Servlet Response]  
[(页码SR2)HTTP Servlet Response设置响应体、发送中文、图片][SR2_HTTP Servlet Response]  
[(页码SR3)HTTP Servlet Response文件下载基本代码][SR3_HTTP Servlet Response]  
[(页码SR4)HTTP Servlet Response一次性验证码的实现][SR4_HTTP Servlet Response]  
整合：HTTP Servlet Response完成文件下载、一次性验证码的实现

[20200222212659138.png]: https://img-blog.csdnimg.cn/20200222212659138.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200222224651652.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1,size_16,color_FFFFFF,t_70
[20200223024128787.png]: https://img-blog.csdnimg.cn/20200223024128787.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200223024044874.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1,size_16,color_FFFFFF,t_70
[20200223034418167.png]: https://img-blog.csdnimg.cn/20200223034418167.png
[SR1_HTTP Servlet Response]: https://blog.csdn.net/qq_40922845/article/details/104444704
[SR2_HTTP Servlet Response]: https://blog.csdn.net/qq_40922845/article/details/104448580
[SR3_HTTP Servlet Response]: https://blog.csdn.net/qq_40922845/article/details/104452337
[SR4_HTTP Servlet Response]: https://blog.csdn.net/qq_40922845/article/details/104460218