我正在尝试通过ajax上传文件，但失败了。在下面的代码中，我总是收到“发生错误”警报。任何帮助表示赞赏。在 IE 中，它说长时间运行脚本，但再次无法上传图像。我尝试仅上传 19KB 文件。
上传.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>File Upload</title>
<script src="cssjs/jquery-1.9.1.js"></script>
</head>
<body>
Select file to upload:
<input type="file" name="dataFile" id="fileChooser"/><br/><br/>
<script type="text/javascript">
$('#fileChooser').change( function(){
$.ajax({
url: '/UploadServlet',
data : { dataFile: document.getElementById('fileChooser') },
type : 'POST',
dataType : 'text',
mimeType: 'multipart/form-data',
contentType: false,
cache: false,
processData:false,
success: function(data, textStatus, jqXHR) {
alert("filePath:" + data);
},
error: function(jqXHR, textStatus, errorThrown) {
alert("error occured");
}
});
e.preventDefault();
});
</script>
</body>
</html>
UploadServlet.java
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadServlet
*/
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String DATA_DIRECTORY = "data";
private static final int MAX_MEMORY_SIZE = 1024 * 1024 * 2;
private static final int MAX_REQUEST_SIZE = 1024 * 1024;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Check that we have a file upload request
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
PrintWriter out = response.getWriter();
if (!isMultipart) {
return;
}
// Create a factory for disk-based file items
DiskFileItemFactory factory = new DiskFileItemFactory();
// Sets the size threshold beyond which files are written directly to
// disk.
factory.setSizeThreshold(MAX_MEMORY_SIZE);
// Sets the directory used to temporarily store files that are larger
// than the configured size threshold. We use temporary directory for
// java
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
// constructs the folder where uploaded file will be stored
String uploadFolder = getServletContext().getRealPath("")
+ File.separator + DATA_DIRECTORY;
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// Set overall request size constraint
upload.setSizeMax(MAX_REQUEST_SIZE);
try {
// Parse the request
List items = upload.parseRequest(request);
Iterator iter = items.iterator();
while (iter.hasNext()) {
FileItem item = (FileItem) iter.next();
if (!item.isFormField()) {
String fileName = new File(item.getName()).getName();
String filePath = uploadFolder + File.separator + fileName;
File uploadedFile = new File(filePath);
System.out.println(filePath);
// saves the file to upload directory
item.write(uploadedFile);
out.write(filePath);
}
}
// displays done.jsp page after upload finished
//getServletContext().getRequestDispatcher("/done.jsp").forward(
//request, response);
} catch (FileUploadException ex) {
throw new ServletException(ex);
} catch (Exception ex) {
throw new ServletException(ex);
}
}
}
最佳答案
首先，无法通过Ajax上传文件。您可以使用IFrame上传文件，而无需刷新页面。
与问题无关，但对程序员有帮助:
您已经使用了e.preventDefault();其中e在哪里？您应该将其传递给 change 事件中的函数。
其次，添加正确的 console.log('error', errorThrown); 并使用 firebug 等工具在控制台中查看它。它抛出错误
组件没有请求的接口(interface)
这就是你应该学习调试的方式。
关于javascript - Ajax文件上传失败，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20772998/