PDF.js展示本地文件

问题：
       pdf.js下载下来之后，接入到应用中之后，可以通过 var DEFAULT_URL = ''; 读取同目录下的pdf文件。但是存在其他磁盘文件就不可以了。

解决思路：
       

Servlet代码如下：

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author Kevin 2018-4-24
 * 
 * pdf处理
 *
 */
@WebServlet("/PDFServlet")
public class PDFServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public PDFServlet() {
        super();
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        /**
         * 此代码仅为示例，具体的防空指针等、业务逻辑需要根据实际情况更改。 2018-4-24
         */

        String paramId = request.getParameter("pdfId"); 
        //下面是伪代码，真正的业务需要查库，得到path
        String path = "";
        if(paramId.equals("1")){
            path = "D:\555\2017-09-116 (1).pdf";
        } else {
            path = "D:\我的开源世界\JDK中的设计模式应用实例-动力节点.pdf";
        }

        InputStream input = null;
        OutputStream out = null;
        try{
            response.setStatus(HttpServletResponse.SC_OK);  
            response.setContentType("application/pdf;charset=UTF-8");  
            input = new BufferedInputStream(new FileInputStream(new File(path)));  
            byte buffBytes[] = new byte[1024];  
            out = response.getOutputStream();  
            int read = 0;    
            while ((read = input.read(buffBytes)) != -1) {    
                out.write(buffBytes, 0, read);    
            }  
        }catch(Exception e){
            e.printStackTrace();
        }finally {
            out.flush();    
            out.close();
        }
    }
}

pdf.js中web/viewer.js中需要将下述代码放到var DEFAULT_URL = ''; 将其重新赋值：

/***************** 定义方法获取本地文件，通过重置URL，让PDFServlet处理流 wgd*******************/

var pdfId = document.getElementById('vie').getAttribute('data');
var DEFAULT_URL = "";//注意，删除的变量在这里重新定义  
var PDFData = "";
//获取应用路径
var localObj = window.location;
var contextPath = localObj.pathname.split("/")[1];
var basePath = localObj.protocol + "//" + localObj.host + "/"+ contextPath;
$.ajax({  
    type:"post",  
    async:false,  //
    mimeType: 'text/plain; charset=x-user-defined',  
    url:basePath+'/PDFServlet?pdfId=' + pdfId,  
    success:function(data){  
       PDFData = data;  
    }  
});  

var rawLength = PDFData.length;  
//转换成pdf.js能直接解析的Uint8Array类型,见pdf.js-4068  
var array = new Uint8Array(new ArrayBuffer(rawLength));    
for(var i = 0; i < rawLength; i++) {  
  array[i] = PDFData.charCodeAt(i) & 0xff;  
}  

DEFAULT_URL = array; 

/*****************wgd 2018-4-24*******************/

引入viewer.js的时候需要将参数，比如：一条附件信息的id传入等，利用下面这种方式即可，当然搜索还有其他的方式可以解决。

<script id="vie" src="<%=request.getContextPath() %>/js/pdf-js/web/viewer.js" 
data="${param.id }"></script>

通过上面的办法，就可以展示存储的本地pdf文件了。

参考：https://www.cnblogs.com/lvmylife/p/6651672.html