如何在xpages中从Java传递对文件的引用
我为我的英语感到抱歉。我使用翻译。Java有一个代码。从数据库中读取字段Posgresql bytea二进制数据,并将其存储在文件中:如何在xpages中从Java传递对文件的引用,java,xpages,xpages-ssjs,xpages-extlib,ssjs,Java,Xpages,Xpages Ssjs,Xpages Extlib,Ssjs,我为我的英语感到抱歉。我使用翻译。Java有一个代码。从数据库中读取字段Posgresql bytea二进制数据,并将其存储在文件中: <code> public static void saveToFile() throws IOException { try { Connection conn = JdbcUtil.getConnection(FacesContext.getCurrentInstance(), "derby1");
<code>
public static void saveToFile() throws IOException {
try {
Connection conn = JdbcUtil.getConnection(FacesContext.getCurrentInstance(), "derby1");
ResultSet rs = conn.createStatement().executeQuery(
"SELECT files FROM test_goverment where who='d'");
byte[] imgBytes = null;
if (rs != null) {
while (rs.next()) {
imgBytes = rs.getBytes(1);
}
FileOutputStream os = new FileOutputStream("c:\\samoutput.txt");
os.write(imgBytes);
os.flush();
os.close();
}
rs.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
enter code here}
}
</code>
如何在Xpages中将要下载的文件传输给用户。下载后将其删除。您只想将查询结果传输到浏览器客户端下载,不想保存 而不是先将查询结果保存到文件中,然后将其传输以供以后下载
您可以流式传输内容直接到XPage的响应,如下所示:
public static void downloadFile() throws IOException {
try {
FacesContext facesContext = FacesContext.getCurrentInstance();
Connection conn = JdbcUtil.getConnection(facesContext, "derby1");
ResultSet rs = conn.createStatement().executeQuery(
"SELECT files FROM test_goverment where who='d'");
byte[] imgBytes = null;
if (rs != null) {
while (rs.next()) {
imgBytes = rs.getBytes(1);
}
ExternalContext extCon = facesContext.getExternalContext();
XspHttpServletResponse response = (XspHttpServletResponse)extCon.getResponse();
response.reset();
response.setContentType("text/plain");
response.setHeader("Content-disposition", "attachment; filename=output.txt");
response.setHeader("Cache-Control", "no-cache");
OutputStream os = response.getOutputStream();
os.write(imgBytes);
os.flush();
facesContext.responseComplete();
rs.close();
}
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
你也可以看看这个。它向您展示了如何呈现文件以供下载,以防您想/不得不保留文件而不是流