为什么Maven使用JDK 1.6但我的java -version是1.7

Question

我是maven的新手,也是MacOS的新手.

我在我的终端设置了maven,当获得版本设置(使用mvn -v)时,似乎它使用了JDK 1.6,而我安装了JDK 1.7.有什么不对的吗？

我输入的命令是:

blues:helloworld Ninja$ java -version

java version "1.7.0_05"
Java(TM) SE Runtime Environment (build 1.7.0_05-b06)
Java HotSpot(TM) 64-Bit Server VM (build 23.1-b03, mixed mode)`

blues:helloworld Ninja$ mvn -v

Apache Maven 3.1.0 (893ca28a1da9d5f51ac03827af98bb730128f9f2; 2013-06-28 10:15:32+0800)
Maven home: /usr/local/Cellar/maven/3.1.0/libexec
Java version: 1.6.0_51, vendor: Apple Inc.
Java home: /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
Default locale: zh_CN, platform encoding: EUC_CN
OS name: "mac os x", version: "10.8.4", arch: "x86_64", family: "mac"

Answer 1

将以下内容添加到您的~/.mavenrc:

export JAVA_HOME=/Library/Java/JavaVirtualMachines/{jdk-version}/Contents/Home

二解决方案:

echo export "JAVA_HOME=\$(/usr/libexec/java_home)" >> ~/.bash_profile

Answer 2

进入

/System/Library/Frameworks/JavaVM.framework/Versions

并更新CurrentJDK指向的符号链接

/Library/Java/JavaVirtualMachines/YOUR_JDK_VERSION/Contents/

例如

cd /System/Library/Frameworks/JavaVM.framework/Versions
sudo rm CurrentJDK
sudo ln -s /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/ CurrentJDK

现在它将立即起作用.

Answer 3

你也可以这样做,

<properties>
      ...  

      <!-- maven-compiler-plugin , aka JAVA Compiler 1.7 -->
      <maven.compiler.target>1.7</maven.compiler.target>
      <maven.compiler.source>1.7</maven.compiler.source>

      ...  
</properties>

Answer 4

您还可以明确告诉maven要编译哪个java版本.您可以尝试添加maven-compiler-plugin到您的pom.

<project>
  [...]
  <build>
    [...]
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>1.7</source>
          <target>1.7</target>
        </configuration>
      </plugin>
    </plugins>
    [...]
  </build>
  [...]
</project>

如果您将maven项目导入IDE,则IDE中可能存在maven设置,用于maven runner正在使用的默认编译器.

Answer 5

它帮助了我.只需将其添加到您的pom.xml中即可.

默认情况下,maven编译器插件使用Java 1.5或1.6,您必须在pom.xml中重新定义它.

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>