java - Ant 没有使用正确的 Java 版本

Question

我在安装了 Java jdk(和 jre)1.6 的 Unix 机器上通过 Eclipse Juno 生成了一个 ant 文件。当在 eclipse 之外运行 ant 时，build.xml 文件所在的机器上，一切顺利。

现在，问题是当我尝试在另一台机器上运行 ant 时，其中同时安装了 jdk 和 jre 1.6。这是我在另一台运行 RedHat 3 的机器上得到的(无法更改):

> ant -version
Apache Ant version 1.5.2-23 compiled on November 12 2003

> java -version
java version "1.6.0_39"
Java(TM) SE Runtime Environment (build 1.6.0_39-b04)
Java HotSpot(TM) Client VM (build 20.14-b01, mixed mode, sharing)

> javac -version
javac 1.6.0_39

> ls -l `which java`
lrwxrwxrwx 1 root root   26 Feb 13 15:22 /usr/bin/java -> /usr/java/default/bin/java*

> ls -l `which javac`
lrwxrwxrwx 1 root root   27 Feb 13 15:22 /usr/bin/javac -> /usr/java/default/bin/javac*

> ls -l /usr/java
total 8
lrwxrwxrwx 1 root root   16 Nov  7 14:19 default -> /usr/java/latest
drwxr-xr-x 7 root root 4096 Feb 13 15:02 jdk1.6.0_39/
drwxr-xr-x 7 root root 4096 Nov  7 14:18 jre1.6.0_37/
lrwxrwxrwx 1 root root   21 Feb 13 15:03 latest -> /usr/java/jdk1.6.0_39

> echo $JAVA_HOME
/usr/java/jdk1.6.0_39/bin/java

当我在 build.xml 文件中添加这一行时，我得到以下结果

build.xml:
<echo message="Java version: ${ant.java.version}"/>

> ant 
  [echo] Java version: 1.4

和编译错误:

  [javac] ...InputManager.java:11: error: Invalid method declaration, method name required.
  [javac]    Map<Double, List<MyObject>> loadFile(File pSelectedFile)
  [javac]              ^
  [javac] ...InputManager.java:11: error: Class or interface declaration expected.
  [javac]    Map<Double, List<MyObject>> loadFile(File pSelectedFile)
  [javac]              ^
  [javac] ...InputManager.java:33: error: Invalid character '@' in input.
  [javac]    @Override
  [javac]           ^
...

现在，问题是:我的 java 安装不正确吗？我对 Ant 做错了吗？

这是 build.xml 文件的快速摘录:

> vim build.xml

<project basedir="." default="build" name="myProject">
  <property environment="env"/>
  <property name="ECLIPSE_HOME" value="/opt/eclipse"/>  <!-- that is also where eclipse is on my 2nd machine -->
  <property name="debuglevel" value="source,lines,vars"/>
  <property name="target" value="1.6"/>
  <property name="source" value="1.6"/>
[some stuff]
  <target name="init">
    <mkdir dir="bin"/>
    <copy includeemptydirs="false" todir="bin">
      <fileset dir="src">
        <exclude name="**/*.java"/>
      </fileset>
    </copy>
  </target>
  <target depends="init" name="build-project">
    <echo message="Java version: ${ant.java.version}"/>
    <javac debug="true" debuglevel="${debuglevel}" destdir="bin" includeantruntime="false" source="${source}" target="${target}">
      <src path="src"/>
      <classpath refid="myProject.classpath"/>
    </javac>
  </target>
</project>

欢迎帮助:)

Answer 1

您的 ant 版本是针对旧版本的 java (2003) 编译的。 Java 1.6 于 2006 年问世。据我所知，您可以让 ant 在旧版本上运行，如下所示:http://www.coderanch.com/t/108814/tools/jdk-version-build-xml :

...............

If Ant has been compiled against 1.5 then you can modify the build task to

<javac source="1.4" target="1.4" ...> ...................... But not the other way around. So I'm guessing you need a fresher version of Ant.

来自 http://ant.apache.org/faq.html#java-version

Redhat ES 3.0 comes installed with ant 1.5.2. Even if you have your PATH and ANT_HOME variables set correctly to a later version of ant, you will always be forced to use the preinstalled version.

To use a later version of ant on this OS you could do the following:

$ ant -version
Apache Ant version 1.5.2-23 compiled on November 12 2003
$ su -
# rpm -e ant ant-libs
# exit
$ hash -r
$ ant -version
Apache Ant version 1.6.2 compiled on July 16 2004