HttpServletRequest 类型未定义方法 getPart(String)

Question

我一直致力于 Java 网络项目，我需要通过 JSP 页面上传图像并将其存储到 MySQL 数据库中。我正在输入可用于 Servlet 3.0 或更高版本的多部分图像。

我一直在使用 getPart("image") 逐个获取图像，但它向我显示以下错误： "The method getPart(String) is undefined for the type HttpServletRequest"

我正在使用的服务器：Tomcat 7
我正在使用的IDE：Eclipse Luna

代码片段如下：

ImageUploadServlet:

package com.nagarro.imagemanagementutility.controller;

import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

import com.nagarro.imagemanagementutility.util.Constants;

/**
* Servlet implementation class ImageUploadServlet
*/
@MultipartConfig(maxFileSize=Constants.MAX_FILE_SIZE)   // Upload image file     size upto 16 MB
public class ImageUploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
 * @see HttpServlet#HttpServlet()
 */
public ImageUploadServlet() {
    super();
}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    InputStream inputStream = null;

    // obtains the upload image file in this multipart request
    Part imagePart = request.getPart("photo");
}

}

UserImageUtility.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>Image Management Utility</title>
</head>
<body>
 <table border="1" align="center" width="900px">
  <tr>
   <td>
    <div align="center">
     <h3>Image Management Utility</h3>
    </div>
   </td>
  </tr>
  <tr>
   <td>
    <div>Please select an image file to upload (Max Size 1 MB)</div>
    &nbsp;
    <form action="ImageUploadServlet" method="post"
     enctype="multipart/form-data">
     <input type="file" name="image" size="50" />
     <div align="right">
      <input type="submit" name="sbtnSubmit" value="Submit" />
      <input type="button" name="btnCancel" value="Cancel" />
     </div>
    </form>
   </td>
  </tr>
 </table>
</body>
</html>

pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>com.nagarro</groupId>
 <artifactId>Assignment_4_ImageManagementUtility</artifactId>
 <packaging>war</packaging>
 <version>0.0.1-SNAPSHOT</version>
 <name>Assignment_4_ImageManagementUtility Maven Webapp</name>
 <url>http://maven.apache.org</url>

 <build>
  <finalName>Assignment_4_ImageManagementUtility</finalName>
  <pluginManagement>
   <plugins>
    <plugin>
     <groupId>org.apache.maven.plugins</groupId>
     <artifactId>maven-jar-plugin</artifactId>
     <configuration>
      <archive>
       <manifest>
        <addClasspath>true</addClasspath>
        <classpathPrefix>lib/</classpathPrefix>
        <mainClass>com.nagarro.imagemanagementutility.controller.ApplicationLauncher</mainClass>
       </manifest>
       <manifestEntries>
        <Class-Path>.</Class-Path>
       </manifestEntries>
      </archive>

      <finalName></finalName>
     </configuration>
    </plugin>
   </plugins>
  </pluginManagement>
 </build>

 <dependencies>
  <dependency>
   <groupId>junit</groupId>
   <artifactId>junit</artifactId>
   <version>3.8.1</version>
   <scope>test</scope>
  </dependency>
  <dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>servlet-api</artifactId>
   <version>3.0-alpha-1</version>
  </dependency>
  <dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>jstl</artifactId>
   <version>1.2</version>
   <scope>runtime</scope>
  </dependency>
  <dependency>
   <groupId>jstl</groupId>
   <artifactId>jstl</artifactId>
   <version>1.2</version>
   <scope>provided</scope>
  </dependency>
  <dependency>
   <groupId>javax.servlet.jsp.jstl</groupId>
   <artifactId>jstl-api</artifactId>
   <version>1.2</version>
  </dependency>
  <dependency>
   <groupId>taglibs</groupId>
   <artifactId>standard</artifactId>
   <version>1.1.2</version>
  </dependency>
  <dependency>
   <groupId>javax.persistence</groupId>
   <artifactId>persistence-api</artifactId>
   <version>1.0.2</version>
  </dependency>
  <dependency>
   <groupId>org.hibernate</groupId>
   <artifactId>hibernate-entitymanager</artifactId>
   <version>4.3.8.Final</version>
  </dependency>
  <dependency>
   <groupId>org.hibernate</groupId>
   <artifactId>hibernate-core</artifactId>
   <version>4.3.8.Final</version>
  </dependency>
  <dependency>
   <groupId>postgresql</groupId>
   <artifactId>postgresql</artifactId>
   <version>9.1-901-1.jdbc4</version>
  </dependency>
  <!-- Hibernate uses slf4j for logging -->
  <dependency>
   <groupId>org.slf4j</groupId>
   <artifactId>slf4j-api</artifactId>
   <version>1.7.10</version>
  </dependency>
  <dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>5.1.6</version>
  </dependency>
 </dependencies>
</project>

lib中的jar列表：

Answer 1

方法

Part getPart(java.lang.String name) throws java.io.IOException, ServletException

在 HttpServletRequest Java EE 6, but not in HttpServletRequest Java EE 5 可用。

确保您使用的是 Java EE 6。

Answer 2

您的 class 路径上有多个 Servlet API jar。 JSTL 太老了，在你的 pom.xml 中有一堆 JSTL 工件拉入旧的 servlet 版本。从您的 pom.xml 中删除 javax.servlet:jstl、jstl:jstl 和 javax.servlet.jsp.jstl:jstl-api，然后试试这个：

<dependency>
    <groupId>org.glassfish.web</groupId>
    <artifactId>jstl-impl</artifactId>
    <version>1.2</version>
    <exclusions>
        <exclusion>
            <groupId>java.servlet</groupId>
            <artifactId>servlet-api</artifactId>
        </exclusion>
        <exclusion>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
        </exclusion>
    </exclusions>
</dependency>

P.S。 Eclipse 将 Tomcat 的 jars 添加到 class 路径，因此您可以根据需要从 pom.xml 中删除 java.servlet:servlet-api。如果你保留它，添加<scope>provided</scope>或Tomcat会抱怨。提供 servlet classes 是 servlet 容器的责任，所以你不应该将它们包含在你的 WAR 中，尽管 Tomcat 足够聪明以防止它成为问题。

HttpServletRequest 类型未定义方法 getPart(String)

The method getPart(String) is undefined for the type HttpServletRequest

java

jsp

servlets

jstl

tomcat7