Question

在jsp中，我从BD获取文件，并希望在客户端上下载：

<%
String num = request.getParameter("param");
Statement sta = null;
sta = conn.createStatement();
String fileName="";
String sql=("SELECT files,filename FROM filestock WHERE num =(SELECT filestock_id FROM parcels_temp WHERE num="+num+")");
ResultSet rs=sta.executeQuery(sql);
while(rs.next()){
    byte[] file = rs.getBytes("files");
    fileName=rs.getString("filename");
}
FileOutputStream fs = new FileOutputStream(new File(fileName));
BufferedOutputStream bs = new BufferedOutputStream(fs);
bs.write(file);
bs.close();
fs.close();
rs.close();
ps.close();
%>

我将PDF文件。所以我有一些问题：
1.我将如何处理文件以将其发送到JavaScript 2.我可以使用ExtJs 3.4或JavaScript保存此文件吗？

更新

现在我尝试将文件从服务器发送到客户端：

<%
String num = request.getParameter("param");
Statement sta = null;
sta = conn.createStatement();
String fileName="";
byte[] file=null;
int bufferSize = 8192;
String sql=("SELECT files,filename FROM filestock WHERE num =(SELECT filestock_id FROM parcels_temp WHERE num="+num+")");
ResultSet rs=sta.executeQuery(sql);
while(rs.next()){
    file = rs.getBytes("files");
    fileName=rs.getString("filename");
}
File dFile=new File(fileName);
InputStream in1 = request.getInputStream();
int read;
while ((read = in1.read(file, 0, bufferSize)) != -1) {
    out.write(file, 0, read);
}
sta.close();
rs.close();
conn.close();
%>

但是得到错误：

The method write(char[], int, int) in the type Writer is not applicable for the arguments (byte[], int, int)

那怎么办呢？

UPDATE2

使用此代码我没有得到任何错误，但在firebug中我看到服务器没有发送给客户端：

<%
String num = request.getParameter("param");
Statement sta = null;
sta = conn.createStatement();
String fileName="";
byte[] file=null;
int bufferSize = 8192;
String sql=("SELECT files,filename FROM filestock WHERE num =(SELECT filestock_id FROM parcels_temp WHERE num="+num+")");
ResultSet rs=sta.executeQuery(sql);
while(rs.next()){
    file = rs.getBytes("files");
    fileName=rs.getString("filename");
}
//File dFile=new File(fileName);
FileOutputStream fout = fout = new FileOutputStream(fileName);
//BufferedInputStream in1 = new BufferedInputStream(fout);
InputStream in1 = request.getInputStream();
int read;
while ((read = in1.read(file, 0, bufferSize)) != -1) {
    fout.write(file, 0, read);
}
sta.close();
rs.close();
conn.close();
%>

Answer 1

您只需创建一个带有Content-Disposition标题的下载网址。

现在好消息/坏消息（取决于观点）。您无法通过JavaScript将文件存储到用户文件系统（期望新的File-API）。但这将沙箱文件系统。因此，您无法使浏览器将该文件存储到某个路径上。

如何使用JavaScript / ExtJs下载文件？

1 个答案: