我想上传多个文件到服务器并在JSP页面中获取参数“testname”。但它总是返回一个空值。 我找到了错误的原因。因为“enctype =“multipart/form-data””。如果我从表单中删除它，我可以获得一个参数，但无法将多个文件上传到服务器。我怎样才能同时完成这两个任务？
lib: http://www.java2s.com/Code/Jar/c/Downloadcosmultipartjar.htm
index.jsp
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<form action="UploadServlet" method="post" enctype="multipart/form-data">
<input name="testname" type="text">
<input type="file" id="file" name="file1" accept="image/*" multiple="muliple" required/><br>
<input type="submit"/>
<br><br> ${requestScope.message}
</form>
</body>
</html>
UploadServlet.java
package MyPackage;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import javax.servlet.*;
import javax.servlet.http.*;
import com.oreilly.servlet.multipart.MultipartParser;
import com.oreilly.servlet.multipart.Part;
import com.oreilly.servlet.multipart.FilePart;
/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/UploadServlet")
public class UploadServlet extends HttpServlet {
private String fileSavePath;
private static final String UPLOAD_DIRECTORY = "Upload";
public void init() {
fileSavePath = getServletContext().getRealPath("/") + File.separator + UPLOAD_DIRECTORY;/*save uploaded files to a 'Upload' directory in the web app*/
if (!(new File(fileSavePath)).exists()) {
(new File(fileSavePath)).mkdir(); // creates the directory if it does not exist
}
}
@Override
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException {
String testname=request.getParameter("testname");
System.out.print(testname);
String resp = "";
int i = 1;
resp += "<br>Here is information about uploaded files.<br>";
try {
MultipartParser parser = new MultipartParser(request, 1024 * 1024 * 1024); /* file limit size of 1GB*/
Part _part;
while ((_part = parser.readNextPart()) != null) {
if (_part.isFile()) {
FilePart fPart = (FilePart) _part; // get some info about the file
String name = fPart.getFileName();
if (name != null) {
long fileSize = fPart.writeTo(new File(fileSavePath));
resp += i++ + ". " + fPart.getFilePath() + "[" + fileSize / 1024 + " KB]<br>";
} else {
resp = "<br>The user did not upload a file for this part.";
}
}
}// end while
} catch (java.io.IOException ioe) {
resp = ioe.getMessage();
}
request.setAttribute("message", resp);
getServletContext().getRequestDispatcher("/index.jsp").forward(request, response);
}
}
最佳答案
使用enctype="multipart/form-data"时，您将无法通过调用request.getParameter()获取参数。这些参数现在是流的一部分。
关于java - Servlet中无法获取参数，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34018623/