Maven - 使用JDK 7编译JVM 5 [英] Maven - Use JDK 7 to Compile for JVM 5

问题描述

我一直试图让它工作一段时间但是还没有运气。

I've been trying to get this to work for a while now but no luck yet.

我想用 JAVA_HOME 指向JDK7，但我想为JVM 5编译一个项目。我读过文档，我发现类似的帖子，但它们似乎都没有在我的设置中工作。

I want to run with JAVA_HOME pointing to JDK7 but I want to compile a project for JVM 5. I've read through documentation, I've found similar posts on SO, but none of them seem to work in my setup.

我是第一个尝试设置目标和源，但我收到错误：

I first tried with setting just target and source but I got an error:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <source>1.5</source>
        <target>1.5</target>
    </configuration>
</plugin>

[ClassName] 不是抽象的，并且不会覆盖 CommonDataSource

[ClassName] is not abstract and does not override abstract method getParentLogger() in CommonDataSource

据我所知，该类已在JDK 7中更新，并且添加了引发错误的额外方法。我需要使用具有旧实现的JDK 5的运行时，一切都应该正常工作。所以我这样做：

As far as I understood that class was updated in JDK 7 and the extra method that's throwing the error was just added. I need to use the runtime of JDK 5 that has the old implementation and everything should work fine. So I do this:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <verbose>true</verbose>
        <source>1.5</source>
        <target>1.5</target>
        <compilerArguments>
            <bootclasspath>${env.JAVA5_HOME}/jre/lib/rt.jar</bootclasspath>
        </compilerArguments>
    </configuration>
</plugin>

我在系统上正确设置了JAVA5_HOME，我可以看到它在日志中加载了正确的类，但是我遇到了另一个错误：

I have JAVA5_HOME set correctly on my system, I can see it loading the correct classes in the log, but I hit another error:

[加载ZipFileIndexFileObject [c：\Program Files \ Java \ _ddk1] .5.0_22\jre\lib\rt.jar(* .class）]]

...

...

[ClassName] 错误：包 javax.crypto 不存在

这是公平的，因为我没有在 jce.jar （加密类）中包含启动类路径。但是有一件事让我很困惑。即使 bootclasspath 仅包含Java 5运行时，我在类路径中也有很多来自JRE7的库。它们没有在任何地方指定。

Which is fair enough, since I didn't include jce.jar (cryptography classes) in the bootclasspath. There is a thing that puzzles me, though. Even though the bootclasspath contains only the Java 5 runtime, I have a lot of libraries from JRE7 in the classpath. They are not specified anywhere.

[类文件的搜索路径：c：\Program Files
（x86）\ Java \ jdk1.5.0_22\jre\lib\rt.jar,c: \Program
Files \ Java \ _Ddk1.7.0_02 \\\\\\\\\\\\\\\\ .jar，c：\Program
Files\Java\jdk1.7.0_02\jre\lib\ext\localedata.jar,c: \Program
Files \ Java \ jdk1.7.0_02\jre\lib\ext\sunec.jar,c: \Program
Files\Java \ jdk1.7.0_02 \ jre \lib \\\ \\ sunjce_provider.jar，c：\Program
Files \ Java @\\\\\ \\ Java \ jdk1.7.0_02 \ jre \ lib \ ecxt \ zipfs.jar，...]

[search path for class files: c:\Program Files (x86)\Java\jdk1.5.0_22\jre\lib\rt.jar,c:\Program Files\Java\jdk1.7.0_02\jre\lib\ext\dnsns.jar,c:\Program Files\Java\jdk1.7.0_02\jre\lib\ext\localedata.jar,c:\Program Files\Java\jdk1.7.0_02\jre\lib\ext\sunec.jar,c:\Program Files\Java\jdk1.7.0_02\jre\lib\ext\sunjce_provider.jar,c:\Program Files\Java\jdk1.7.0_02\jre\lib\ext\sunmscapi.jar,c:\Program Files\Java\jdk1.7.0_02\jre\lib\ext\zipfs.jar, ...]

如果我尝试添加jce.jar（来自JRE5），我会回到第一个错误：

If I try and add jce.jar (from JRE5), I get back to the first error:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <verbose>true</verbose>
        <source>1.5</source>
        <target>1.5</target>
        <compilerArguments>
            <bootclasspath>${env.JAVA5_HOME}/jre/lib/rt.jar${path.separator}${env.JAVA5_HOME}/jre/lib/jce.jar</bootclasspath>
        </compilerArguments>
    </configuration>
</plugin>

类型[ClassName]必须实现继承的抽象方法
CommonDataSource.getParentLogger（）

The type [ClassName] must implement the inherited abstract method CommonDataSource.getParentLogger()

我也看不到 rt.jar 正在加载，但我没有得到 java.lang 找不到错误，所以在类路径上加载了一些类。

I also see no trace of rt.jar being loaded, but I don't get a java.lang not found error, so there are some classes being loaded on the classpath.

我会在构建之前制作一个覆盖 JAVA_HOME 的批处理脚本并暂时修复它，但我真的希望这样做是正确的办法。这似乎不是一个极端的用例。 ：）

I'll fix it temporarily by making a batch script that overwrites JAVA_HOME before building and sets it back afterwards, but I really want this done the right way. This doesn't seem as such an extreme use-case. :)

我在这里做错了什么？

推荐答案

这个答案是针对问题的标题，而不是针对问题的具体问题。

我最终使用了这个解决方案我的项目，允许我通过激活maven配置文件选择性地使用自定义引导类路径。我强烈建议为此使用配置文件，否则它会使没有设置环境变量的任何人的构建失败（非常糟糕，特别是对于开源项目）。
我只在我的IDE中激活此配置文件以进行清理和构建操作。

I ended up using this solution in my project, which allows me to use the custom bootstrap classpath selectively, by activating a maven profile. I strongly recommend using a profile for this, because otherwise it makes the build fail for anyone that does not have the environment variable set (very bad, especially for an open source project). I only activate this profile in my IDE for the "Clean & Build" action.

    <profile>
        <id>compileWithJava5</id>
        <!--
            NOTE
            Make sure to set the environment variable JAVA5_HOME
            to your JDK 1.5 HOME when using this profile.
        -->
        <properties>
            <java.5.home>${env.JAVA5_HOME}</java.5.home>
            <java.5.libs>${java.5.home}/jre/lib</java.5.libs>
            <java.5.bootclasspath>${java.5.libs}/rt.jar${path.separator}${java.5.libs}/jce.jar</java.5.bootclasspath>
        </properties>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.5</source>
                        <target>1.5</target>
                        <compilerArguments>
                            <bootclasspath>${java.5.bootclasspath}</bootclasspath>
                        </compilerArguments>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </profile>

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