Linux -- Ubuntu搭建java开发环境

Steps

1. 1
   Check to see if your Ubuntu Linux operating system
   architecture is 32-bit or 64-bit, open up a terminal and run the following
   command below.
   
   • Type/Copy/Paste: file /sbin/init
     
     • Note the bit version of your Ubuntu Linux operating system
       architecture it will display whether it is 32-bit or 64-bit.



2. 2
   Check if you have Java installed on your
   system. To do this, you will have to run the Java
   version command from terminal.
   
   • Open up a terminal and enter the following command:
     
     • Type/Copy/Paste: java -version
   
   
   • If you have OpenJDK installed on your system it may look like this:
     
     • java version "1.7.0_15"
       OpenJDK Runtime Environment
       (IcedTea6 1.10pre) (7b15~pre1-0lucid1)
       OpenJDK 64-Bit
       Server VM (build 19.0-b09, mixed mode)
   
   
   • If you have OpenJDK installed on your system, you have the wrong vendor
     version of Java installed for this exercise.


3. 3
   Completely remove the OpenJDK/JRE from your system and
   create a directory to hold your Oracle Java JDK/JRE
   binaries. This will prevent system conflicts and
   confusion between different vendor versions of Java. For example, if you have
   the OpenJDK/JRE installed on your system, you can remove it by typing the
   following at the command line:
   
   • Type/Copy/Paste: sudo apt-get purge
     openjdk-\*
     
     • This command will completely remove OpenJDK/JRE from your
       system
   
   
   • Type/Copy/Paste: sudo mkdir -p
     /usr/local/java
     
     • This command will create a directory to hold your Oracle Java JDK and
       JRE binaries.


4. 4
   Download the Oracle Java JDK for
   Linux. Make sure you select
   the correct compressed
   binaries for your system architecture 32-bit or 64-bit (which end in tar.gz).
   
   • For example, if you are on Ubuntu Linux 32-bit operating system download
     32-bit Oracle Java binaries.
   
   
   • For example, if you are on Ubuntu Linux 64-bit operating system download
     64-bit Oracle Java binaries.
   
   
   • Optional, Download the Oracle Java JDK
     Documentation
     
     • Select jdk-7u45-apidocs.zip
   
   
   • Important Information: 64-bit Oracle
     Java binaries do not work on 32-bit Ubuntu Linux operating systems, you will
     receive multiple system error messages, if you attempt to install 64-bit
     Oracle Java on 32-bit Ubuntu Linux.


5. 5
   Copy the Oracle Java binaries into the /usr/local/java
   directory. In most cases, the Oracle Java binaries
   are downloaded to: /home/"your_user_name"/Downloads.
   
   • 32-bit Oracle Java on 32-bit Ubuntu Linux installation
     instructions:
     
     • Type/Copy/Paste: cd
       /home/"your_user_name"/Downloads
     
     
     • Type/Copy/Paste: sudo cp -r
       jdk-7u45-linux-i586.tar.gz /usr/local/java
     
     
     • Type/Copy/Paste: cd
       /usr/local/java
   
   
   • 64-bit Oracle Java on 64-bit Ubuntu Linux installation
     instructions:
     
     • Type/Copy/Paste: cd
       /home/"your_user_name"/Downloads
     
     
     • Type/Copy/Paste: sudo cp -r
       jdk-7u45-linux-x64.tar.gz /usr/local/java
     
     
     • Type/Copy/Paste: cd
       /usr/local/java


6. 6
   Run the following commands on the downloaded Oracle Java
   tar.gz files. Make sure to do this as root in order to make them
   executable for all users on your system. To open a root terminal type sudo -s
   you will be prompted for your logon password.
   
   • 32-bit Oracle Java on 32-bit Ubuntu Linux installation
     instructions:
     
     • Type/Copy/Paste: sudo chmod a+x
       jdk-7u45-linux-i586.tar.gz
   
   
   • 64-bit Oracle Java on 64-bit Ubuntu Linux installation
     instructions:
     
     • Type/Copy/Paste: sudo chmod a+x
       jdk-7u45-linux-x64.tar.gz


7. 7
   Unpack the compressed Java binaries, in the directory
   /usr/local/java
   
   • 32-bit Oracle Java on 32-bit Ubuntu Linux installation
     instructions:
     
     • Type/Copy/Paste: sudo tar xvzf
       jdk-7u45-linux-i586.tar.gz
   
   
   • 64-bit Oracle Java on 64-bit Ubuntu Linux installation
     instructions:
     
     • Type/Copy/Paste: sudo tar xvzf
       jdk-7u45-linux-x64.tar.gz


8. 8
   Double-check your
   directories. At this point, you should have two
   uncompressed binary directories in /usr/local/java for the Java JDK/JRE listed
   as:
   
   • Type/Copy/Paste: ls -a
   
   
   • jdk1.7.0_45


9. 9
   Edit the system PATH file /etc/profile and add the
   following system variables to your system path. Use
   nano, gedit or any other text editor, as root, open up /etc/profile.
   
   • Type/Copy/Paste: sudo gedit
     /etc/profile
   
   
   • or
   
   
   • Type/Copy/Paste: sudo nano
     /etc/profile


10. 10
    Scroll down to the end of the file using your arrow keys
    and add the following lines below to the end of your /etc/profile
    file:
    
    • Type/Copy/Paste:
      
      JAVA_HOME=/usr/local/java/jdk1.7.0_45
      
      PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
      export JAVA_HOME
      export PATH


11. 11
    Save the /etc/profile file and exit.


12. 12
    Inform your Ubuntu Linux system where your Oracle Java
    JDK/JRE is located. This will tell the system that
    the new Oracle Java version is available for use.
    
    • Type/Copy/Paste: sudo
      update-alternatives --install "/usr/bin/java" "java"
      "/usr/local/java/jdk1.7.0_45/bin/java" 1
      
      • this command notifies the system that Oracle Java JRE is available for
        use
    
    
    • Type/Copy/Paste: sudo
      update-alternatives --install "/usr/bin/javac" "javac"
      "/usr/local/java/jdk1.7.0_45/bin/javac" 1
      
      • this command notifies the system that Oracle Java JDK is available for
        use
    
    
    • Type/Copy/Paste: sudo
      update-alternatives --install "/usr/bin/javaws" "javaws"
      "/usr/local/java/jdk1.7.0_45/bin/javaws" 1
      
      • this command notifies the system that Oracle Java Web start is
        available for use


13. 13
    Inform your Ubuntu Linux system that Oracle Java JDK/JRE
    must be the default Java.
    
    • Type/Copy/Paste: sudo
      update-alternatives --set java /usr/local/java/jdk1.7.0_45/bin/java
      
      • this command will set the java runtime environment for the
        system
    
    
    • Type/Copy/Paste: sudo
      update-alternatives --set javac /usr/local/java/jdk1.7.0_45/bin/javac
      
      • this command will set the javac compiler for the system
    
    
    • Type/Copy/Paste: sudo
      update-alternatives --set javaws /usr/local/java/jdk1.7.0_45/bin/javaws
      
      • this command will set Java Web start for the
        system


14. 14
    Reload your system wide PATH /etc/profile by typing the
    following command:
    
    • Type/Copy/Paste: . /etc/profile
    
    
    • Note your system-wide PATH /etc/profile file will reload after reboot of
      your Ubuntu Linux system


15. 15
    Test to see if Oracle Java was installed correctly on
    your system. Run the following commands and note
    the version of Java:


16. 16
    A successful installation of 32-bit Oracle Java will
    display:
    
    • Type/Copy/Paste: java -version
      
      • This command displays the version of java running on your
        system
    
    
    • You should receive a message which displays:
      
      • java version "1.7.0_45"
        Java(TM) SE Runtime
        Environment (build 1.7.5_45-b18)
        Java HotSpot(TM)
        Server VM (build 24.45-b08, mixed mode)
    
    
    • Type/Copy/Paste: javac -version
      
      • This command lets you know that you are now able to compile Java
        programs from the terminal.
    
    
    • You should receive a message which displays:
      
      • javac 1.7.0_45


17. 17
    A successful installation of Oracle Java 64-bit will
    display:
    
    • Type/Copy/Paste: java -version
      
      • This command displays the version of java running on your
        system
    
    
    • You should receive a message which displays:
      
      • java version "1.7.0_45"
        Java(TM) SE Runtime
        Environment (build 1.7.5_45-b18)
        Java HotSpot(TM)
        64-Bit Server VM (build 24.45-b08, mixed mode)
    
    
    • Type/Copy/Paste: javac -version
      
      • This command lets you know that you are now able to compile Java
        programs from the terminal.
    
    
    • You should receive a message which displays:
      
      • javac 1.7.5_40


18. 18
    Congratulations, you just installed Oracle Java on your
    Linux system. Now reboot your Ubuntu Linux system.
    Afterwards, your system will be fully configured for running and developing
    Java programs. Later on you may want to try compiling and running your own
    Java programs by following this article How to Create your First Java Program on Ubuntu
    Linux

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