spring boot + mybatis 读取数据库
创建数据库
use testdb;
drop table if exists t_city;
create table t_city(
id int primary key auto_increment,
city varchar(20),
state varchar(10)
)engine = innodb default charset = utf8;
insert into t_city values(1,"zhengzhou","HN");
maven 的pom 文件
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>nulijiushimeili</groupId>
<artifactId>spring-boot2-mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>spring-boot2-mybatis</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.4</version>
</dependency>
<!-- alibaba的druid数据库连接池 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.9</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
spring boot 配置 application.yml
#默认使用配置
spring:
profiles:
active: dev
#公共配置与profiles选择无关 mapperLocations指的路径是src/main/resources
mybatis:
typeAliasesPackage: com.xdd.entity
# mapperLocations: classpath:mapper/*.xml
---
#开发配置
spring:
profiles: dev
datasource:
url: jdbc:mysql://localhost:3306/testdb
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
# 使用druid数据源
type: com.alibaba.druid.pool.DruidDataSource
spring boot 启动器
@SpringBootApplication
@EnableTransactionManagement //如果mybatis中service实现类中加入事务注解,需要此处添加该注解
@MapperScan("nulijiushimeili.springboot2mybatis.mapper") //扫描的是mapper.xml中namespace指向值的包位置
public class SpringBoot2MybatisApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBoot2MybatisApplication.class, args);
}
}
City bean
public class City {
private String city;
private String state;
public City(){}
public City(String city, String state){
this.city = city ;
this.state = state;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
}
mapper
@Repository
public interface CityMapper {
@Select("select * from t_city where state = #{state}")
City findByState(@Param("state")String state);
}
controller
@Controller
@RequestMapping(value = "/abv")
public class RegistyController {
@Autowired
private CityMapper cityMapper;
@RequestMapping(value = "/read", method = RequestMethod.GET)
@ResponseBody
public City readMybatis(@RequestParam String state) {
return cityMapper.findByState(state);
}
}
测试url
http://localhost:8080/abv/read?state=HN
踩坑记
- 数据库的字段名和bean的字段名必须保持一致,前后台请求数据的key也必须是一致的。否则会加载不到数据
- 映射url请求路径不对,比如在类名上添加了@RequestMapping(),在请求的时候只写了类名上了方法上的路径。
spring boot 和 ajax 进行前后台交互