原文鏈接 :?http://blog.csdn.net/done58/article/details/51138057

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1, 查看Java版本

打開Mac電腦，查看JAVA版本，打開終端Terminal，通過命令行查看筆者的java版本：：?

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1. bogon:~?donny$?java?-version??
2. java?version?"1.7.0_71"??
3. Java(TM)?SE?Runtime?Environment?(build?1.7.0_71-b14)??
4. Java?HotSpot(TM)?64-Bit?Server?VM?(build?24.71-b01,?mixed?mode)??

發(fā)現(xiàn)已安裝Java運(yùn)行環(huán)境。如果你的系統(tǒng)已經(jīng)安裝成功JDK，通過java -version就可以看到相應(yīng)的jdk版本。如果你的電腦還沒有安裝JDK的話，可以到Oracle官網(wǎng)下載jdk。

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2, 查看JAVA安裝路徑

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1. bogon:~?donny$?which?java??
2. /usr/bin/java??
3. bogon:~?donny$?whereis?java??
4. /usr/bin/java??
5. bogon:~?donny$???

通過ls -l ?/usr/bin/java 不能找到真實(shí)的安裝路徑，通過搜索發(fā)現(xiàn)了這篇文章Important Java Directories on Mac OS X，?https://developer.apple.com/library/mac/qa/qa1170/_index.html。

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Many?Java?applications need to know the location of a?$JAVA_HOME?directory. The?$JAVA_HOME?on Mac OS X should be found using the?/usr/libexec/java_home?command line tool on Mac OS X 10.5 or later. On older Mac OS X versions where the tool does not exist, use the fixed path "/Library/Java/Home". The?/usr/libexec/java_home?tool dynamically finds the top?java?version specified in Java Preferences for the current user. This path allows access to the?bin?subdirectory where command line tools such as?java,?javac, etc. exist as on other platforms. The tool?/usr/libexec/java_home?allows you to specify a particular CPU architecture and Java platform version when locating a?$JAVA_HOME.

Another advantage of dynamically finding this path, as opposed to hardcoding the fixed endpoint, is that it is updated when a new version of Java is downloaded via Software Update or installed with a newer version of Mac OS X. For this reason, it is important that developers do not install files in the JDKs inside of?/System, since the changes will be lost with subsequent updates by newer versions of Java.

To obtain the path to the currently executing?$JAVA_HOME, use the?java.home?System property.

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1. bogon:~?donny$?ls?-l?/usr/libexec/java_home??
2. lrwxr-xr-x??1?root??wheel??79?Nov??1?15:43?/usr/libexec/java_home?->?/System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java_home??

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這還是沒定位到真實(shí)的位置。根據(jù)網(wǎng)上搜索Mac OSX 10.9以后系統(tǒng)就自帶了Java 6的環(huán)境，路徑在:

/Library/Java/JavaVirtualMachines文件夾下。下面看這個(gè)路徑的結(jié)果是什么樣？

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1. bogon:Home?donny$?cd?/Library/Java/JavaVirtualMachines??
2. bogon:JavaVirtualMachines?donny$?ls???
3. jdk1.7.0_71.jdk??

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可以看到真實(shí)的JDK在這里了，最終的路徑是：

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1. /Library/Java/JavaVirtualMachines/jdk1.7.0_71.jdk/Contents/Home??

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可以參照蘋果的文件文檔說明，在命令 /usr/libexec/java_home 后面使用-V選項(xiàng)列出所有版本的JAVA_HOME，即如下的結(jié)果:

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1. bogon:Home?donny$?/usr/libexec/java_home?-V??
2. Matching?Java?Virtual?Machines?(1):??
3. ????1.7.0_71,?x86_64:???"Java?SE?7"?/Library/Java/JavaVirtualMachines/jdk1.7.0_71.jdk/Contents/Home??
4. /Library/Java/JavaVirtualMachines/jdk1.7.0_71.jdk/Contents/Home??

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3, 設(shè)置JAVA_HOME環(huán)境變量

cd回到用戶目錄，再列出當(dāng)前的所有文件，可以見到當(dāng)前系統(tǒng)的.開頭的所有文件。

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1. bogon:Home?donny$?cd??
2. bogon:~?donny$?ls?-a??

添加java_home到.bash_profile文件中

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export JAVA_HOME=$(/usr/libexec/java_home)
export PATH=$JAVA_HOME/bin:$PATH
export CLASS_PATH=$JAVA_HOME/lib 需要說明的是Mac OSX 10.5之后蘋果就建議設(shè)置$JAVA_HOME變量到/usr/libexec/java_home，添加完畢之后，按esc退出插入模式，并鍵入wq!保存退出文件。

到這個(gè)步驟，我們就已經(jīng)配置好了全局的java的path和classpath環(huán)境變量。以后就可以好好的進(jìn)行java開發(fā)了。

轉(zhuǎn)載于:https://www.cnblogs.com/dfyg-xiaoxiao/p/7103238.html

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