這邊用一個簡單的servlet實現java從服務端下載檔案的操作

 寫一個servlet：

  <servlet>
    <servlet-name>DownloadServlet</servlet-name>
    <servlet-class>DownloadServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>DownloadServlet</servlet-name
 
>
    <url-pattern>/download</url-pattern>
  </servlet-mapping>

java程式碼：

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import
 
 java.io.OutputStream;

public class DownloadServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        String filePath = "D:\\360MoveData\\Users\\123\\Desktop\\WebComponents.exe";
        String fileName = "WebComponents.exe";
        String fileType 
 
= "application/octet-stream";

        //設定檔案的型別
        response.setContentType(fileType);
        // 確保彈出下載對話方塊
        response.setHeader("Content-disposition", "attachment; filename=" + fileName);
        FileInputStream inputStream = new FileInputStream(filePath);
        //輸出流
        OutputStream outputStream = response.getOutputStream();
        byte[] bytes = new byte[4096];
        int length;
        while ((length = inputStream.read(bytes)) > 0){
            outputStream.write(bytes, 0, length);
        }
        inputStream.close();
        outputStream.flush();
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
        doGet(request, response);
    }
}