last modified September 10, 2020
mysql # 设置mysql客户端默认字符集 default-character-set=utf8 mysqld #设置3306端口 port = 3306 # 设置mysql的安装目录 basedir=C: Program Files mysql-5.6.39-winx64 # 设置mysql数据库的数据的存放目录 datadir=C: Program Files mysql-5.6.39-winx64 data # 允许最大连接数 maxconnections=200 # 服务端使用的字符集默认为8比特编码的latin1字符集. 「mysqlsecureinstallation」コマンドを利用すると、対話形式にrootパスワード変更や、その他初期設定がかんたんにおこなえます。こちらを利用して設定をおこないましょう。 $ mysqlsecureinstallation Securing the MySQL server deployment.
Spring Boot MySQL tutorial shows how to use MySQL database in a Spring Bootapplication.
Spring is a popular Java application framework for creatingenterprise applications. Spring Boot is an evolution of Springframework which helps create stand-alone, production-grade Spring basedapplications with minimal effort.
MySQL
MySQL is a leading open source database management system. It isa multi-user, multithreaded database management system. MySQL is especiallypopular on the web. It is one part of the very popular LAMP platform,which includes Linux, Apache, MySQL, and PHP. MySQL database is availableon most important OS platforms. It runs on BSD Unix, Linux, Windows, and Mac.
MySQL setup
We are going to show how to install MySQL database on a Debian Linux system.
This command installs MySQL server and related packages.
These two commands are used to start and stop MySQL.
We check the status of the database with systemctl status mysqlcommand.
Now we need to reset the root password. We start the mysql command line tool.(The server must be running.) We connect as root.
We set a new password for root.
We can use mysql_secure_installation to increase security of MySQLserver. We are given the choice to improve the MySQL root password, removeanonymous user accounts, disable root logins outside of localhost, and removetest databases.
We create a new testdb database.
We create a new MySQL user and grant it privileges to the testdbdatabase.
Creating MySQL table
Now we are going to create a new MySQL table called cities.
This is SQL to create the cities table.
With the source command, we execute the SQL statements.
Spring Boot MySQL example
The following application is a simple Spring Boot web application, which usesMySQL database. We have a home page with a link to display data from a databasetable. We use Freemarker templating system to join data with HTML.
This is the project structure.
Spring Boot starters are a set of convenient dependency descriptors whichgreatly simplify Maven configuration. The spring-boot-starter-parent has some common configurations for aSpring Boot application. The spring-boot-starter-web is a starterfor building web, including RESTful, applications using Spring MVC. Thespring-boot-starter-freemarker is a starter for building MVC webapplications using Freemarker views. The spring-boot-starter-data-jpa is a starter for using Spring Data JPA with Hibernate.
The mysql-connector-java dependency is for the MySQL database driver.
The spring-boot-maven-plugin provides Spring Boot support in Maven, allowing us to package executable JAR or WAR archives. Its spring-boot:rungoal runs the Spring Boot application.
In the application.properties file we write various configurationsettings of a Spring Boot application. With the spring.main.banner-mode property we turn off the Spring banner. With the logging.level.org.springframework we set the logging level for spring framework to ERROR.In the spring datasource properties we set up the MySQL datasource.
This is the City entity. Each entity must have at least twoannotations defined: @Entity and @Id.
The @Entity annotation specifies that the class is anentity and is mapped to a database table while the @Table annotationspecifies the name of the database table to be used for mapping.
The primary key of an entity is specified with the @Id annotation.The @GeneratedValue gives a strategy for generating the values of primary keys.
By extending from the Spring CrudRepository, we will havesome methods for our data repository implemented, including findAll().This way we save a lot of boilerplate code.
ICityService provides the findAll() contractmethod declaration to get all cities from the data source.
CityService contains the implementation of the findAll() method. We use the repository to retrieve data from the database.
CityRepository is injected.
The findAll() method of the repository returns the list ofcities.
MyController class is annotated with @Controller.
We inject an ICityService into the countryServicefield.
We map a request with the /cities path to the controller'sfindCities method. The @GetMapping annotation maps a GET request to the method. The model gains a list of cities and the processing issent to the showCities.ftlh Freemarker template file.
In the showCities.ftlh template file, we display the data inan HTML table.
In the index.html there is a link to show all cities.
The Application sets up the Spring Boot application.The @SpringBootApplication enables auto-configuration andcomponent scanning.
Mysql_secure_installation Access Denied Mac
After the application is run, we can navigate to localhost:8080.
In this tutorial, we have showed how to use MySQL database ina Spring Boot application.
Mysql_secure_installation Access Denied
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