java下载东西

Love The Way You Lie 2021-11-27 07:12 262阅读 0赞

package com.gxs.controller;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.ServletOutputStream;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.apache.tomcat.jni.OS;
    
    import com.sun.jndi.url.corbaname.corbanameURLContextFactory;
    
    /**
     * Servlet implementation class Hei
     */
    @WebServlet("/download")
    public class Hei extends HttpServlet {
        
    	private static final long serialVersionUID = 1L;
    
    	/**
    	 * @see HttpServlet#HttpServlet()
    	 */
    	public Hei() {
        
    		super();
    	}
    
    	/**
    	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
    	 *      response)
    	 */
    	protected void doGet(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
        
    		// TODO Auto-generated method stub
    //		ServletContext servletContext = getServletContext();
    //		Object attribute = servletContext.getAttribute("name");
    //		System.out.println(attribute);
    
    //		获取需要下载的文件路径名
    		String filename = request.getParameter("filename");
    //		更改文件路径的真实路径
    		ServletContext servletContext = request.getServletContext();
    		String realPath = servletContext.getRealPath("download/" + filename);
    
    //		根据路径创建输入流
    		FileInputStream fileInputStream = new FileInputStream(realPath);
    //		告诉浏览器不要解析，直接下载
    		String mimeType = servletContext.getMimeType(filename);// 获取文件类型
    		response.setHeader("content-type", mimeType);
    		response.setHeader("content-disposition", "attachment;filename=" + filename);
    
    //		获取输入流对象
    		OutputStream outputStream = response.getOutputStream();
    //		边读边写
    		int len = 0;
    		byte[] b = new byte[1024];
    		while ((len = fileInputStream.read(b)) != -1) {
        
    			outputStream.write(b, 0, len);
    		}
    //		释放资源
    		fileInputStream.close();
    		outputStream.close();
    
    //		String header = response.getHeader(filename);
    //		System.out.println(header);
    
    	}
    
    	/**
    	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
    	 *      response)
    	 */
    	protected void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
        
    		// TODO Auto-generated method stub
    		doGet(request, response);
    	}
    
    }

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