Mybatis-plus introductory tutorial (a)

What MyBatis-Plus

Plus-MyBatis (abbreviated MP) is a MyBatis enhancement tools, enhanced not only change on the basis of MyBatis, to simplify development tedious CRUD, improved code efficiency and health, while providing a code generator and pagination plug-in, support Spring boot, spring mvc development.

what is the benefit

Property

• Non-invasive : not only enhance the change, it will not have an impact on the introduction of existing projects, such as silky smooth
• Loss is small : the basic injection start automatically CURD i.e., substantially no loss of performance, object-oriented operating direct
• Powerful CRUD operations : built-in universal Mapper, Universal Service, the configuration can be achieved only by a small amount of single-table most of the CRUD operations, more powerful conditions constructors, to meet the various needs
• Lambda forms of support calls : The Lambda expressions, easy preparation of various types of query conditions, without having to worry about the wrong field
• Automatic generation of primary key support : supports up to four primary key strategies (Distributed contains a unique ID generator - Sequence), freely configurable, perfect to solve the primary key issue
• Support ActiveRecord model : ActiveRecord form of support calls, just like an entity class inherits Model can be a powerful CRUD operations
• Support custom global General Procedure : general procedure supports global injection (Write once, use anywhere)
• Built-in code generator : the use of code or Maven plugin can quickly generate Mapper, Model, Service, Controller layer code, support template engine, more and more super custom configuration waiting for you to use
• Built-in pagination plug-in : after MyBatis based on physical pages, developers need not concern specific operations, configure the plug-in, written paging equivalent to general inquiries List
• Pagination plug-in supports multiple databases : support for MySQL, MariaDB, Oracle, DB2, H2, HSQL, SQLite, Postgre, SQLServer and other databases
• Built-in performance analysis plug-ins : Sql statement can be output as well as its execution time, this feature is enabled recommends that developers test time, can quickly ferret out slow query
• Built-in global blocking plug-ins : Provide a full table delete, update operational intelligence analysis block, also can customize the blocking rules to prevent misuse

Support Database

• mysql 、 mariadb 、 oracle 、 db2 、 h2 、 hsql 、 sqlite 、 postgresql 、 sqlserver
• Dream up a database, Xu Gu database, the NPC gold warehouse database

Framework

Integration with a spring boot

Add pom.xml dependence

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.1.RELEASE</version>
    <relativePath/>

</parent>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.2.0</version>
    </dependency>
    
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.0</version>
    </dependency>
 
    <!-- 提供mysql驱动 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
</dependencies>

Configuration application.yml

server:
  port: 80
spring:
  application: 
     name: mp
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.driver
    url: jdbc:mysql://localhost:3306/mp?autoReconnect=true&useSSL=false&allowPublicKeyRetrieval=true
    username: root
    password: 1234
mybatis-plus: 
   mapper-locations:classpath: mapper/*Mapper.xml
   type-aliases-package: com.mp.entity

Create a startup class MpApplication.java

@EnableTransactionManagement
@SpringBootApplication
@MapperScan("com.yiyang.mapper")
public class MpApplication {

    public static void main(String[] args) {
        SpringApplication.run(MpApplication.class, args);
    }
}

Creating the Entity Classes

@Data
@TableName("user")
public class User {
    @TableId(type=IdType.INPUT)
    private Long id;
    @TableField
    private String name;
    @TableField
    private Integer age;
    @TableField
    private String email;
    /**...setter,getter......*/
}

Run on the Ok