Gentoo 安裝Xfce4圖形介面
阿新 • • 發佈:2020-12-31
java 的hello world
1.jdk12.0.2官網路徑(往期的各個版本):http://jdk.java.net/archive/
2.選擇macos版本
3.解壓並放到合適的目錄
4.進入目錄Home,終端執行一下命令,生成jre
@bogon Home % bin/jlink --module-path jmods --add-modules java.desktop --output jre
5.配置環境變數(多jdk時動態切換)
@bogon ~ % vi .bash_profile
# java
# 設定jdk8
export JAVA_8_HOME= '/Library/Java/JavaVirtualMachines/jdk1.8.0_231.jdk/Contents/Home'
# 設定jdk12
export JAVA_12_HOME='/Library/Java/JavaVirtualMachines/jdk-12.0.2.jdk/Contents/Home'
# 預設jdk8
export JAVA_HOME=$JAVA_8_HOME
# 動態切換jdk
alias jdk8='export JAVA_HOME=$JAVA_8_HOME'
alias jdk12='export JAVA_HOME=$JAVA_12_HOME'
# java END
@bogon ~ % source .bash_profile
@bogon ~ % java -version
java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)
@bogon ~ % jdk12
@bogon ~ % java -version
openjdk version "12.0.2" 2019-07-16
OpenJDK Runtime Environment ( build 12.0.2+10)
OpenJDK 64-Bit Server VM (build 12.0.2+10, mixed mode, sharing)
@bogon ~ % jdk8
@bogon ~ % java -version
java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)
@bogon ~ %
vim編輯一個java檔案:
public class HelloWorld{
public static void main(String[] args){
System.out.println("hello world!");
}
}
(對應java檔案路徑位置)命令列中:
//編譯java檔案,生成.class檔案
[email protected] Documents % javac HelloWorld.java
//解釋class檔案
[email protected] Documents % java HelloWorld
hello world!
簡單傳參:
public class HelloWorld{
public static void main(String[] args){
System.out.println("hello world!");
for(int i =0;i<args.length;i++){
System.out.println("args"+i+":"+args[i]);
}
}
}
重新編譯後,傳參
[email protected] Documents % java HelloWorld 1 2 3
hello world!
args0:1
args1:2
args2:3