java实现文件下载

文件下载实例：

public String download() throws Exception{
HttpServletResponse response = this.getResponse();
        System.out.println("下载准备");
        //1.设置文件ContentType类型，这样设置，会自动判断下载文件类型  
        response.setContentType("multipart/form-data");  
        //2.设置文件头：最后一个参数是设置下载文件名，并用UTF-8编码  
        response.setHeader("Content-Disposition", "attachment;fileName="+URLEncoder.encode("月报表.xls", "UTF-8"));  
        ServletOutputStream out;  
        //通过文件路径获得File对象(假如此路径中有一个月报表.xls文件)  
        File file = new File("F:/月报表.xls");  
        try {  
            FileInputStream inputStream = new FileInputStream(file);  
            //3.通过response获取ServletOutputStream对象(out)  
            out = response.getOutputStream();
            int b = 0;  
            byte[] buffer = new byte[512];  
            while (b != -1){  
                b = inputStream.read(buffer);  
            //4.写到输出流(out)中  
                out.write(buffer,0,b);  
            }  
            inputStream.close();  
            out.close();  
            out.flush();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  

        System.out.println("下载完成");
        return "reportpage";
    }

该段代码，已经在程序中运行过，可以正常运行，实现下载。