新Spring项目构建失败

Question

我完全是Spring的初学者。我已经安装了jdk和maven…

< code > echo＄JAVA _ HOME 显示:

/Library/Java/JavaVirtualMachines/jdk-9.0.4.jdk/Contents/Home

< code>$ javac -version显示:

javac 9.0.4

mvn-版本显示：

Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T08:58:13+01:00)
Maven home: /usr/local/Cellar/maven/3.5.2/libexec
Java version: 9.0.4, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk-9.0.4.jdk/Contents/Home
Default locale: en_GB, platform encoding: UTF-8
OS name: "mac os x", version: "10.13.2", arch: "x86_64", family: "mac"

到目前为止，我所做的唯一一件事就是创建一个名为“controller”的包，包内有一个“HomeController.java”文件，代码如下:

package com.demo.spring.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class HomeController {

    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String index(){

        return "Hello World.";
    }
}

但当我运行＜code＞mvn spring boot：run＜/code＞时，我得到：

[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.561 s
[INFO] Finished at: 2018-01-17T13:28:14Z
[INFO] Final Memory: 25M/83M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:1.5.9.RELEASE:run (default-cli) on project demo: Could not exec java: Application finished with exit code: 1 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

我以前没有接触过spring，所以安装了jdk(通过java网站)和maven(通过homebrew ),并按照教程在intellij中设置spring应用程序，我不知道我做错了/没做什么。我看到错误引用无法执行java，提供的链接指出这是一个插件问题，但我如何解决这个问题？

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>com.demo.spring</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo-spring</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

Answer 1

我认为所有这些错误都与 Java 9有关。

Maven建议对 Java 9进行一些更改，您可以使用它们，例如：

>

添加 Java 9 作为属性：

对于 Spring 启动插件失败，修复 spring-boot-maven-plugin

更多信息，请访问这个博客。

Answer 2

您当前的 jdk 版本是 1.9.0，但在 pom 中.xml它指向 1.8，因此您需要将该版本更改为 1.9。

以下是您的版本

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

换成1.9的

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.9</java.version>
    </properties>

then try to run below command 

mvn clean spring-boot:run