为了获取多张图片,我正在调用一个名为 PhotoHelperServlet
的服务,使用锚标签来获取图片名称(多张图片),如下所示
使用 PhotoHelperServlet
来获取 Images
的名称
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Getting userid from session
Image image = new Image();
image.setUserid(userid);
ImageDAO imageDAO = new ImageDAO();
try {
List<Image> imageId = imageDAO.listNames(image);
if (imageId == null) {
// check if imageId is retreived
}
request.setAttribute("imageId", imageId);
//Redirect it to home page
RequestDispatcher rd = request.getRequestDispatcher("/webplugin/jsp/profile/photos.jsp");
rd.forward(request, response);
catch (Exception e) {
e.printStackTrace();
}
在ImageDAO的listNames()方法中:
public List<Image> listNames(Image image) throws IllegalArgumentException, SQLException, ClassNotFoundException {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultset = null;
Database database = new Database();
List<Image> imageId = new ArrayList<Image>();
try {
connection = database.openConnection();
preparedStatement = connection.prepareStatement(SQL_GET_PHOTOID);
preparedStatement.setLong(1, image.getUserid());
resultset = preparedStatement.executeQuery();
while(resultset.next()) {
image.setPhotoid(resultset.getLong(1));
imageId.add(image);
}
} catch (SQLException e) {
throw new SQLException(e);
} finally {
close(connection, preparedStatement, resultset);
}
return imageId;
}
在JSP代码中:
<c:forEach items="${imageId}" var="imageid">
<img src="Photos/${imageid}">
</c:forEach>
在PhotoServlet的doGet()方法中获取照片:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String imageid = request.getPathInfo().substring(1);
if(imageid == null) {
// check for null and response.senderror
}
ImageDAO imageDAO = new ImageDAO();
try {
Image image = imageDAO.getPhotos(imageid);
if(image == null) {}
BufferedInputStream input = null;
BufferedOutputStream output = null;
try {
input = new BufferedInputStream(image.getPhoto(), DEFAULT_BUFFER_SIZE);
output = new BufferedOutputStream(response.getOutputStream(), DEFAULT_BUFFER_SIZE);
// Write file contents to response.
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
int length;
while ((length = input.read(buffer)) > 0) {
output.write(buffer, 0, length);
}
} finally {
if (output != null) try { output.close(); } catch (IOException logOrIgnore) {}
if (input != null) try { input.close(); } catch (IOException logOrIgnore) {}
}
} catch(Exception e) {
e.printStackTrace();
}
在ImageDAO的getPhotos()方法中。public Image getPhotos(String imageid) throws IllegalArgumentException, SQLException, ClassNotFoundException {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultset = null;
Database database = new Database();
Image image = new Image();
try {
connection = database.openConnection();
preparedStatement = connection.prepareStatement(SQL_GET_PHOTO);
preparedStatement.setString(1, imageid);
resultset = preparedStatement.executeQuery();
while(resultset.next()) {
image.setPhoto(resultset.getBinaryStream(1));
}
} catch (SQLException e) {
throw new SQLException(e);
} finally {
close(connection, preparedStatement, resultset);
}
return image;
}
在 web.xml 文件中。<!-- Getting each photo -->
<servlet>
<servlet-name>Photos Module</servlet-name>
<servlet-class>app.controllers.PhotoServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Photos Module</servlet-name>
<url-pattern>/Photos/*</url-pattern>
</servlet-mapping>
<!-- Getting photo names -->
<servlet>
<servlet-name>Photo Module</servlet-name>
<servlet-class>app.controllers.PhotoHelperServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Photo Module</servlet-name>
<url-pattern>/Photo</url-pattern>
</servlet-mapping>
问题:
我遇到了以下异常:
java.io.IOException: Stream closed
在这一行代码中:
at app.controllers.PhotoServlet.doGet(PhotoServlet.java:94)
while ((length = input.read(buffer)) > 0) {
完整异常信息:
java.io.IOException: Stream closed
at java.io.BufferedInputStream.getInIfOpen(BufferedInputStream.java:134)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:256)
at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
at java.io.FilterInputStream.read(FilterInputStream.java:90)
at app.controllers.PhotoServlet.doGet(PhotoServlet.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
image.getPhoto()
没有任何照片(值)在里面吗? - a k