一.新建一个SpringBoot
构建准备
- jdk 1.8 或以上
- maven
- IntelliJ IDEA
打开Idea-> new Project ->Spring Initializr ->填写group、artifact ->钩上web(开启web功能）->点下一步就行了。
创建完工程，工程的目录结构如下：
- pom文件为基本的依赖管理文件
- resouces 资源文件
- statics 静态资源
- templates 模板资源
- application.properties 配置文件（后面更换成.yml）
- SpringbootApplication程序的入口
POM文件配置参考
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.springboot</groupId>
<artifactId>mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>mybatis</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<mybatis-plus.version>3.0.6</mybatis-plus.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- 模板引擎 代码生成 -->
<dependency>
<groupId>org.apache.velocity</groupId>
<artifactId>velocity</artifactId>
<version>1.7</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
创建Controller
@RestController
public class HelloWordController {
@RequestMapping("/")
public String index() {
return "Hello This is Spring Boot Test!";
}
}
启动项目，在浏览器中输入： http://localhost:8080/
可以看到输出
一.集成建一个mybatis-plus
1）pom新增配置
<!-- mybatisplus与springboot整合 -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatisplus-spring-boot-starter</artifactId>
<version>1.0.5</version>
</dependency>
<!-- MP 核心库 -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus</artifactId>
<version>2.1.8</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<!-- 模板引擎 代码生成 -->
<dependency>
<groupId>org.apache.velocity</groupId>
<artifactId>velocity</artifactId>
<version>1.7</version>
</dependency>
<!-- connection pool -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.18</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
2）修改application.yml
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/test20191031
username: root
password: 123456
#mybatis
mybatis-plus:
mapper-locations: classpath*:mapper/**/*.xml
#实体扫描，多个package用逗号或者分号分隔
typeAliasesPackage: com.honghh.bootfirst.entity
global-config:
#主键类型 0:"数据库ID自增", 1:"用户输入ID",2:"全局唯一ID (数字类型唯一ID)", 3:"全局唯一ID UUID";
id-type: 0
#字段策略 0:"忽略判断",1:"非 NULL 判断"),2:"非空判断"
field-strategy: 2
#驼峰下划线转换
db-column-underline: true
#刷新mapper 调试神器
refresh-mapper: true
#数据库大写下划线转换
#capital-mode: true
# Sequence序列接口实现类配置
#key-generator: com.baomidou.mybatisplus.incrementer.OracleKeyGenerator
#逻辑删除配置
#logic-delete-value: -1
#logic-not-delete-value: 0
#自定义填充策略接口实现
#meta-object-handler: com.baomidou.springboot.xxx
#自定义SQL注入器
sql-injector: com.baomidou.mybatisplus.mapper.LogicSqlInjector
configuration:
map-underscore-to-camel-case: true
cache-enabled: false
call-setters-on-nulls: true
3)新增Mapper及xml配置，结构如下（如能力强可参考自动生成）
/**
* <p>
* Mapper 接口
* </p>
*
* @author WUql123
* @since 2019-11-01
*/
public interface MyInfoMapper extends BaseMapper<MyInfo> {
}
MyInfoMapper.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.springboot.mybatis.mapper.MyInfoMapper"> </mapper>
4）映射数据库实体类
public5 class MyInfo implements Serializable {
private static final long serialVersionUID = 1L;
@TableId(value = "id", type = IdType.AUTO)
private Integer id;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "MyInfo{" +
"id=" + id +
", name=" + name +
", age=" + age +
"}";
}
}
5）新建接口服务类 extends （com.springboot.mybatis.service）IService
@Service
public interface MyInfoService extends IService<MyInfo> {
}
服务实现类
@Service
public class MyInfoServiceImpl extends ServiceImpl<MyInfoMapper, MyInfo> implements MyInfoService {
}
6.新建一个控制类用于测试
@Controller
@RequestMapping("/myInfo")
public class MyInfoController {
@Resource
MyInfoService myInfoService;
@GetMapping("/getInfo")
public String myInfo(@RequestParam Integer id) {
MyInfo myInfo = myInfoService.selectById(id);
System.out.println(myInfo.toString());
return myInfo.toString();
}
}
7.浏览器测试
http://localhost:8080/myInfo/getInfo?id=1
结果输出
MyInfo{id=1, name=lus, age=18}
则完成一个简单的查询
注：例子涉及到的表结构
CREATE TABLE `my_info` (
`id` int(10) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`age` int(3) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;