CentOS 7 配置Java语言开发环境

初始化设置参考：http://blog.csdn.net/wh211212/article/details/52923673

安装JDK8

安装Java SE开发工具包8（JDK8）并构建Java环境

• 下载并安装JDK 8
• [确保Oracle下载站点上JDK的最新版本和源URL]http://www.oracle.com/technetwork/java/javase/downloads/index.html

[root@linuxprobe ~]# curl -L "http://download.oracle.com/otn-pub/java/jdk/8u121-b13/e9e7ea248e2c4826b92b3f075a80e441/jdk-8u121-linux-x64.rpm" -H "Cookie: oraclelicense=accept-securebackup-cookie"  -H "Connection: keep-alive" -O# 采用yum或者rpm方式安裝jdk（這裡一yum為例）[root@linuxprobe ~]# yum localinstall jdk-8u121-linux-x64.rpm -yLoaded plugins: fastestmirrorExamining jdk-8u121-linux-x64.rpm: 2000:jdk1.8.0_121-1.8.0_121-fcs.x86_64Marking jdk-8u121-linux-x64.rpm to be installedResolving Dependencies--> Running transaction check---> Package jdk1.8.0_121.x86_64 2000:1.8.0_121-fcs will be installed--> Finished Dependency ResolutionDependencies Resolved=============================================================================================================================================================================================================================================================================== Package                                                         Arch                                                      Version                                                               Repository                                                               Size===============================================================================================================================================================================================================================================================================Installing: jdk1.8.0_121                                                    x86_64                                                    2000:1.8.0_121-fcs                                                    /jdk-8u121-linux-x64                                                    263 MTransaction Summary===============================================================================================================================================================================================================================================================================Install  1 PackageTotal size: 263 MInstalled size: 263 MDownloading packages:Running transaction checkRunning transaction testTransaction test succeededRunning transaction  Installing : 2000:jdk1.8.0_121-1.8.0_121-fcs.x86_64                                                                                                                                                                                                                      1/1Unpacking JAR files...    tools.jar...    plugin.jar...    javaws.jar...    deploy.jar...    rt.jar...    jsse.jar...    charsets.jar...    localedata.jar...  Verifying  : 2000:jdk1.8.0_121-1.8.0_121-fcs.x86_64                                                                                                                                                                                                                      1/1Installed:  jdk1.8.0_121.x86_64 2000:1.8.0_121-fcsComplete![root@linuxprobe ~]# java -versionjava version "1.8.0_121"Java(TM) SE Runtime Environment (build 1.8.0_121-b13)Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)# 設置jdk環境變量[root@linuxprobe ~]# vi /etc/profile# add follows to the endexport JAVA_HOME=/usr/java/defaultexport PATH=$PATH:$JAVA_HOME/binexport CLASSPATH=.:$JAVA_HOME/jre/lib:$JAVA_HOME/lib:$JAVA_HOME/lib/tools.jar[root@linuxprobe ~]# source /etc/profile

参考链接：http://blog.csdn.net/gsls200808/article/details/52336745（使用curl和wget下载最新版JDK）

• 如果安装了另一个版本的JDK，请更改默认值，如下所示：

# 以java-1.8.0-openjdk為例[root@linuxprobe ~]# yum install java-1.8.0-openjdk -y[root@linuxprobe ~]# alternatives --config javaThere are 2 programs which provide 'java'.  Selection    Command-----------------------------------------------   1           /usr/java/jdk1.8.0_121/jre/bin/java*+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.121-0.b13.el7_3.x86_64/jre/bin/java)# 选择通过yum安装的最新版的Oracle JDKEnter to keep the current selection[+], or type selection number: 1

• 创建测试程序确保java环境正常

[root@linuxprobe ~]# vi day.java import java.util.Calendar;class day {    public static void main(String[] args) {        Calendar cal = Calendar.getInstance();        int year = cal.get(Calendar.YEAR);        int month = cal.get(Calendar.MONTH) + 1;        int day = cal.get(Calendar.DATE);        int hour = cal.get(Calendar.HOUR_OF_DAY);        int minute = cal.get(Calendar.MINUTE);        System.out.println(year + "/" + month + "/" + day + " " + hour + ":" + minute);    }}# compile[root@linuxprobe ~]# javac day.java [root@linuxprobe ~]# java day2017/4/12 21:49