使用Maven在Java Servlet中找不到的類

Question

我嘗試使用Maven從Google導入Gson庫，但是當我運行我的Web應用程序時，我收到錯誤，找不到Gson類。 我試圖為Gson庫的范圍提供但它沒有做任何事情。

的pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>groupId</groupId>
    <artifactId>Skeleton</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.6.2</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</project>

TestServlet.java

package servlets;

import com.google.gson.Gson;
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.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by Philippe on 2016-05-10.
 */
@WebServlet(name = "/TestServlet")
public class TestServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> list = new ArrayList<String>() ;
        list.add("item1");
        list.add("item2");
        Gson gson = new Gson() ;
        String json = gson.toJson(list) ;
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write(json);
    }
}

日志

java.lang.ClassNotFoundException：com.google.gson.Gson，位於org.apache.catalina.loader.WebappClassLoaderBase.loadClass（WebappClassLoaderBase.java:1305），位於org.apache.catalina.loader.WebappClassLoaderBase.loadClass（WebappClassLoaderBase.java:1139 ）at servlets.TestServlet.doGet（TestServlet.java:34）at javax.servlet.http.HttpServlet.service（HttpServlet.java:622）at javax.servlet.http.HttpServlet.service（HttpServlet.java:729）

有什么我想念的嗎？

Answer 1

只需嘗試刪除站點中記錄的<scope>compile</scope> 。

<!-- http://mvnrepository.com/artifact/com.google.code.gson/gson -->
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.6.2</version>
</dependency>