Teach you how to build java, Tomcat, MySQL in linux environment! ! !

One, install Java

0, upload jdk to the specified directory

1. Unzip and move to the specified directory

unzip:

tar -zxvf jdk-8u152-linux-x64.tar.gz

Create a directory:

mkdir -p /usr/local/java

Mobile installation package:

mv jdk1.8.0_152/ /usr/local/java/

Set owner:

chown -R root:root /usr/local/java/

2. Configure environment variables

Configure system environment variables:

vim /etc/environment #打开environment 文件
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"
export JAVA_HOME=/usr/local/java/jdk1.8.0_231
export JRE_HOME=/usr/local/java/jdk1.8.0_231/jre
export CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib

Configure user environment variables:

vim /etc/profile #打开profile 文件

export JAVA_HOME=/usr/local/java/jdk1.8.0_231
export JRE_HOME=/usr/local/java/jdk1.8.0_231/jre
export CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH:$HOME/bin

Enable user environment variables to take effect

source /etc/profile

3. Verify that the installation is successful

java -version

Two, install Tomcat

1. Unzip and move to the specified directory

unzip:

tar -zxvf apache-tomcat-9.5.35.tar.gz

Change directory:

mv apache-tomcat-9.0.35 tomcat

2. Verify that the installation is successful

Start: enter the bin directory of tomcat

./startup.sh

stop:

./shutdown.sh

Three, install MySQL

1. Installation

Update the data source:

yum update

Download and install the official Yum Repository of MySQL:

wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm

Use yum command to install mysql57-community-release-el7-10.noarch.rpm

yum -y install mysql57-community-release-el7-10.noarch.rpm

Install mysql server

yum -y install mysql-community-server

2. Start MySQL

systemctl start  mysqld.service

View the execution status of MySQL

systemctl status mysqld.service

3. Check the database password:

Go to the /var/log directory to view the mysqld.log file. Use / add the password you want to search to see the password initialized by mysql itself. My password here is: 6sBelK-eMajY

4. Connect to the database

Check it

select * from dual;

An error was reported, the reason is that before executing the statement, you must use the ALTER USER statement to reset the password

ALTER USER 'root'@'localhost' IDENTIFIED BY 'admin123';

It was wrong! ! ! [Password policy problem exception information]

First set a slightly more complicated

ALTER USER 'root'@'localhost' IDENTIFIED BY 'ZHANGadmin123.';

View password policy:

SHOW VARIABLES LIKE 'validate_password%'; 

5. About mysql password policy related parameters:

1. validate_password_length The total length of the fixed password
2. validate_password_dictionary_file specifies the file path for password verification
3. validate_password_mixed_case_count The entire password must contain at least the total number of uppercase and lowercase letters
4. validate_password_number_count The entire password must contain at least the number of Arabic numerals
5. validate_password_policy specifies the password strength verification level. The default
   value is MEDIUM . The value of validate_password_policy:
   0/LOW: only verify length
   1/MEDIUM: verify length, numbers, uppercase and lowercase, special characters
   2/STRONG: verify length, numbers, uppercase and lowercase, Special characters, dictionary files
6. validate_password_special_char_count The entire password must contain at least the number of special characters

Modify the password rules [Don't do this online]
1. Change the password verification level to only verify length
2. Set the length to 5

and then test again.

You're done! ! !

6. Attention! ! !

But there is still a problem at this time, because the Yum Repository is installed, and every yum operation will be automatically updated in the future, you need to uninstall this: mysql57-community-release-el7-10.noarch
exit the database first

yum -y remove mysql57-community-release-el7-10.noarch

7. Remote connection

It is impossible to perform data operations here, let's connect with Navicat, but woc can't connect
! ! !

Don't worry! Follow the steps below to modify it:

use mysql; #选择数据库
update user set host ='%' where user = 'root'; # 修改远程机器访问 root 用户
flush privileges;

connection succeeded! ! !

Writing is not easy to focus on three batter, I will always continue to look forward to the next phase of the output ... linux configuration Thank you!
Encourage you...