将以下代码行添加到你的.zshrc(或bash_profile):

alias j='f(){export JAVA_HOME=/usr/libexec/ JAVA_HOME -v $1};f'

保存到会话:

$ source .zshrc

执行命令(例如j13, j14, j1.8…)

$ j 1.8

解释 这是参数化的，所以你不需要像其他解决方案一样更新脚本。如果您没有安装JVM，系统会告诉您。案例示例如下:

/Users/user/IDE/project $ j 1.8
/Users/user/IDE/project $ java -version
openjdk version "1.8.0_265"
OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_265-b01)
OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.265-b01, mixed mode)
/Users/user/IDE/project $ j 13
/Users/user/IDE/project $ java -version
openjdk version "13.0.2" 2020-01-14
OpenJDK Runtime Environment (build 13.0.2+8)
OpenJDK 64-Bit Server VM (build 13.0.2+8, mixed mode, sharing)
/Users/user/IDE/project $ j 1.7
Unable to find any JVMs matching version "1.7".

除了上面的答案，我在我的.bash_profile(或MacOS 10.15+的.zshrc)中添加了以下几行，这使得切换非常方便(包括java 9的@elektromin的注释):

alias j12="export JAVA_HOME=`/usr/libexec/java_home -v 12`; java -version"
alias j11="export JAVA_HOME=`/usr/libexec/java_home -v 11`; java -version"
alias j10="export JAVA_HOME=`/usr/libexec/java_home -v 10`; java -version"
alias j9="export JAVA_HOME=`/usr/libexec/java_home -v 9`; java -version"
alias j8="export JAVA_HOME=`/usr/libexec/java_home -v 1.8`; java -version"
alias j7="export JAVA_HOME=`/usr/libexec/java_home -v 1.7`; java -version"

插入后，执行$ source .bash_profile

我可以通过输入以下命令切换到Java 8:

$ j8
java version "1.8.0_102"
Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)

博士tl;

加一行:

出口JAVA_HOME = ' /图书馆/ Java / JavaVirtualMachines / jdk1.8.0_144.jdk /内容/家庭的

到文件

~ / . bash_profile

(取代jdk1.8.0_144。JDK的下载版本)

然后源~/.bash_profile

来自Apple官方java_home(1)手册页:

**USAGE**

   /usr/libexec/java_home  helps  users  set a $JAVA_HOME in their login rc files, or provides a way for
   command-line Java tools to use the most appropriate JVM which can satisfy a minimum version or archi-
   tecture  requirement.  The --exec argument can invoke tools in the selected $JAVA_HOME/bin directory,
   which is useful for starting Java command-line tools from launchd plists without hardcoding the  full
   path to the Java command-line tool.

   Usage for bash-style shells:
          $ export JAVA_HOME=`/usr/libexec/java_home`

   Usage for csh-style shells:
          % setenv JAVA_HOME `/usr/libexec/java_home`

macOS El Capitan或更新版本将选择/Library/Java/JavaVirtualMachines中可用的更高版本的JDK，因此为了降级，您可以将文件重命名为Info。plist改为Info.plist.disabled这样操作系统就会选择以前的版本。

首先找出存储环境变量的位置

emacs bash_profile zshrc中

设置环境变量步骤:- .单击“确定”

从JAVA下载jdk 双击安装它 现在在文件中设置环境变量 a. emacs。你可以使用这个链接或看到下面的截图

b.对于ZSH配置文件设置-

1. export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_112.jdk/Contents/Home

2. source ~/.zshrc - Restart zshrc to reflect the changes.

3. echo $JAVA_HOME - make sure path is set up properly 
   ----> /Library/Java/JavaVirtualMachines/jdk1.8.0_112.jdk/Contents/Home

4. java -version 

   -->  java version "1.8.0_112"  Java(TM) SE Runtime Environment (build 1.8.0_112-b16)Java HotSpot(TM) 64-Bit Server VM (build 25.112-b16, mixed mode)

所有设置现在您可以轻松升级或降级JAVA版本..