内核版本：
[root@heima01 java]# uname -a
Linux heima01 2.6.32-573.el6.i686 #1 SMP Thu Jul 23 12:37:35 UTC 2015 i686 i686 i386 GNU/Linux
发行版本：
[root@heima01 java]# lsb_release -a
LSB Version: :base-4.0-ia32:base-4.0-noarch:core-4.0-ia32:core-4.0-noarch:graphics-4.0-ia32:graphics-4.0-noarch:printing-4.0-ia32:printing-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 6.7 (Final)
Release: 6.7
Codename: Final
安装目录：
/usr/local/java
示例：jdk压缩包解压后，/usr/local/java/jdk1.7.0_71
原始jdk文件保存目录：
当前用户主目录/develop
1.查看是否已经安装了jdk
1.1 $ java -version
已经安装
[heima01@heima01 ~]$ java -version
java version "1.7.0_79"
OpenJDK Runtime Environment (rhel-2.5.5.4.el6-i386 u79-b14)
OpenJDK Client VM (build 24.79-b02, mixed mode, sharing)
没有安装
[root@heima01 heima01]# java -version
bash: /usr/bin/java: No such file or directory
1.2 $ rpm -qa | grep java
[heima01@heima01 ~]$ rpm -qa | grep java
tzdata-java-2015e-1.el6.noarch
java-1.6.0-openjdk-1.6.0.35-1.13.7.1.el6_6.i686
java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
1.3 $ yum list installed | grep java
[heima01@heima01 ~]$ yum list installed | grep java
java-1.6.0-openjdk.i686 1:1.6.0.35-1.13.7.1.el6_6
java-1.7.0-openjdk.i686 1:1.7.0.79-2.5.5.4.el6
tzdata-java.noarch 2015e-1.el6 @anaconda-CentOS-201508042139.i386/6.7
2.查看安装的软件安装在哪里
2.1 $ rpm -ql java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
步骤:先通过rpm -qa搜索出的软件，再通过rpm -ql查看文件目录。
[heima01@heima01 ~]$ rpm -ql java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
/etc/.java
/etc/.java/.systemPrefs
/usr/lib/jvm-exports/java-1.7.0-openjdk-1.7.0.79
/usr/lib/jvm-exports/java-1.7.0-openjdk-1.7.0.79/jaas-1.7.0.79.jar
/usr/lib/jvm-exports/java-1.7.0-openjdk-1.7.0.79/jaas-1.7.0.jar
/usr/lib/jvm-exports/java-1.7.0-openjdk-1.7.0.79/jaas.jar
/usr/lib/jvm-exports/java-1.7.0-openjdk-1.7.0.79/jce-1.7.0.79.jar
3.卸载已经安装的jdk
3.1 $ rpm -e tzdata-java-2015e-1.el6.noarch
解释：-e 参数用于卸载软件包，但是如果有依赖于该安装包的已经安装项，则会卸载失败。
[heima01@heima01 ~]$ rpm -e tzdata-java-2015e-1.el6.noarch
error: Failed dependencies:
tzdata-java is needed by (installed) java-1.7.0-openjdk-1:1.7.0.79-2.5.5.4.el6.i686
tzdata-java is needed by (installed) java-1.6.0-openjdk-1:1.6.0.35-1.13.7.1.el6_6.i686
3.2 # rpm -e --nodeps tzdata-java-2015e-1.el6.noarch
[root@heima01 heima01]# rpm -e tzdata-java-2015e-1.el6.noarch
error: Failed dependencies:
tzdata-java is needed by (installed) java-1.7.0-openjdk-1:1.7.0.79-2.5.5.4.el6.i686
tzdata-java is needed by (installed) java-1.6.0-openjdk-1:1.6.0.35-1.13.7.1.el6_6.i686
[root@heima01 heima01]# rpm -e --nodeps tzdata-java-2015e-1.el6.noarch
[root@heima01 heima01]# rpm -qa | grep java
java-1.6.0-openjdk-1.6.0.35-1.13.7.1.el6_6.i686
java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
//--nodeps参数删除tzdata-java-2015e-1.el6.noarch，基于这个依赖的java-1.7.0-openjdk-1:1.7.0.79-2.5.5.4.el6.i686仍能够运行
[root@heima01 heima01]# java -version
java version "1.7.0_79"
OpenJDK Runtime Environment (rhel-2.5.5.4.el6-i386 u79-b14)
OpenJDK Client VM (build 24.79-b02, mixed mode, sharing)
权限问题：
[heima01@heima01 ~]$ rpm -e --nodeps tzdata-java-2015e-1.el6.noarch
error: can't create transaction lock on /var/lib/rpm/.rpm.lock (Permission denied)
解决方案：
$ su //登录root用户，再进行删除操作
[heima01@heima01 ~]$ su
Password:
[root@heima01 heima01]# ls
3.3 删除java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
[root@heima01 heima01]# rpm -e java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
error: Failed dependencies:
jre >= 1.5.0 is needed by (installed) libreoffice-ure-1:4.2.8.2-11.el6.i686
libjawt.so is needed by (installed) libreoffice-core-1:4.2.8.2-11.el6.i686
libjawt.so(SUNWprivate_1.1) is needed by (installed) libreoffice-core-1:4.2.8.2-11.el6.i686
[root@heima01 heima01]# rpm -e --nodeps java-1.7.0-openjdk-1.7.0.79-2.5.5.4.el6.i686
4.安装jdk
4.1 存储上传的jdk: /root/develop
[root@heima01 develop]# ls
apache-tomcat-7.0.94.tar.gz jdk-7u75-linux-x64.tar.gz mysql-8.0.13-1.el7.x86_64.rpm-bundle.tar server-jre-8u212-linux-x64.tar.gz
[root@heima01 develop]# pwd
/root/develop
4.2 将jdk解压到/usr/local/java目录下
创建/usr/local/java目录
示例：# mkdir /usr/local/java
[root@frxx ~]# ls /usr/local
bin etc games include lib lib64 libexec sbin share src
[root@frxx ~]# mkdir /usr/local/java
[root@frxx ~]# ls /usr/local
bin etc games include java lib lib64 libexec sbin share src
将压缩包解压到/usr/local/java目录下
示例：tar -xvf /root/develop/jdk-7u75-linux-x64.tar.gz -C /usr/local/java
[root@heima01 /]# pwd
/
[root@heima01 /]# tar -xvf /root/develop/jdk-7u75-linux-x64.tar.gz -C /usr/local/java
[root@heima01 /]# ls /usr/local/java/
jdk1.7.0_75
4.3 设置环境变量
修改配置文件/etc/profile
编辑/etc/profile文件，添加环境变量：
export JAVA_HOME=/usr/local/java/jdk1.7.0_75
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$JAVA_HOME/bin:$PATH
让配置生效：
[root@heima01 /]# source /etc/profile
问题：
描述:cannot execute binary file
原因：安装jdk的版本或位数和linux系统版本或位数不匹配
[root@heima01 /]# java
bash: /usr/local/java/jdk1.7.0_75/bin/java: cannot execute binary file
Linux版本：2.6.32-573.el6.i686
[root@heima01 /]# uname -a
Linux heima01 2.6.32-573.el6.i686 #1 SMP Thu Jul 23 12:37:35 UTC 2015 i686 i686 i386 GNU/Linux
JDK版本：jdk-7u75-linux-x64.tar.gz
[root@heima01 /]# ls /root/develop/
apache-tomcat-7.0.94.tar.gz jdk-7u75-linux-x64.tar.gz
方案：使用i686 Linux对应的jdk，jdk-7u71-linux-i586.tar.gz
[root@heima01 java]# ls /root/develop/
apache-tomcat-7.0.94.tar.gz jdk-7u71-linux-i586.tar.gz jdk-7u75-linux-x64.tar.gz mysql-8.0.13-1.el7.x86_64.rpm-bundle.tar server-jre-8u212-linux-x64.tar.gz
验证安装成功：
示例：# java -version
[root@heima01 java]# java -version
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) Client VM (build 24.71-b01, mixed mode)
