linux配置JDK
#### 一:从官网下载[jdk下载官网](https://www.oracle.com/java/technologies/downloads/)压缩包解压即可
+ jdk11版本之前(添加以下内容)
+ $ vim /home/user用户名/.bashrc
```js|jdk
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
export JRE_HOME=$JAVA_HOME/jre
export CLASSPATH=$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
```
+ jdk11版本之后
+ vim /home/user用户名/.bashrc
```js|jdk
export JAVA_HOME=/opt/jdk-17.0.3.1
export CLASSPATH=$JAVA_HOME/lib
export PATH=$JAVA_HOME/bin:$PATH
```
#### 二:更新配置才能生效
```js|jdk
$ source .bashrc
```
#### 三:验证
```js|jdk
$ java --version
输出以下则为成功
$ openjdk 11.0.1 2018-10-16
$ OpenJDK Runtime Environment 18.9 (build 11.0.1+13)
$ OpenJDK 64-Bit Server VM 18.9 (build 11.0.1+13, mixed mode)
```
#### 四:Mac os配置java环境(如果没有.zshrc就新建)
```js|jdk
1.$ touch .zshrc
2.$ vim .zshrc(填写以下内容)
JAVA_HOME=/Users/mac/jdk-11.0.15.jdk/Contents/Home(自己jdk包的路径)
PATH=$JAVA_HOME/bin:$PATH:.
CLASSPATH=$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar:.
export JAVA_HOME
export PATH
export CLASSPATH
```
生效
```js|jdk
source .zshrc
```