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)