通过java controller将pdf下载到web系统中

package com.example.getorder.Controller;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import sun.misc.BASE64Decoder;

import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

@Controller
@RequestMapping("textcontroller")
public class TestController {


    @ResponseBody
    @RequestMapping("downloadpdf")
    public String getStream(String uri,HttpServletRequest request) {

        try {
           String savePath=  downLoadFromUrl(request,uri);
           return savePath;
        }catch (Exception e)
        {
            e.printStackTrace();
        }

        return "";
    }

    /**
     * 从网络Url中下载文件
     * @param urlStr
     * @throws IOException
     */
    public static String  downLoadFromUrl(HttpServletRequest request, String urlStr) throws IOException{
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        //设置超时间为3秒
        conn.setConnectTimeout(3*1000);
        //防止屏蔽程序抓取而返回403错误
        conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

        //得到输入流
        InputStream inputStream = conn.getInputStream();
        //获取自己数组
        byte[] getData = readInputStream(inputStream);
        String basePath="/WEB-INF/pdfjs/web";
        String path = request.getSession().getServletContext().getRealPath(basePath);
       // String savePath=TestController.class.getClassLoader().getResource("").getPath();
        //文件保存位置
        File saveDir = new File(path);
        if(!saveDir.exists()){
            saveDir.mkdir();
        }
        File file = new File(saveDir+File.separator+"dingdan.pdf");
        FileOutputStream fos = new FileOutputStream(file);
        fos.write(getData);
        if(fos!=null){
            fos.close();
        }
        if(inputStream!=null){
            inputStream.close();
        }

        return path+"dingdan.pdf";

     //   System.out.println("info:"+url+" download success");

    }



    /**
     * 从输入流中获取字节数组
     * @param inputStream
     * @return
     * @throws IOException
     */
    public static  byte[] readInputStream(InputStream inputStream) throws IOException {
        byte[] buffer = new byte[1024];
        int len = 0;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        while((len = inputStream.read(buffer)) != -1) {
            bos.write(buffer, 0, len);
        }
        bos.close();
        return bos.toByteArray();
    }


}

再用一行代码将保存到本地的pdf打开

<a href="#" onclick="window.open('<%=basePath%>pdfjs/web/viewer.html?file=/pdfjs/web/dingdan.pdf','PDF','width:50%;height:50%;top:100;left:100;');">查看pdf</a> 

即可