SpringBoot无废话入门04：MyBatis整合

1.Parent引入及pom配置

首先，如果要支持mybatis，那么我们就应该引入mybatis的starter。同时，由于连接本身还需要用jdbc的connetor和连接池，所以一并需要引入这些依赖。如下是一个完整的的最简pom，

<?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/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>

<packaging>war</packaging>

<parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>2.1.3.RELEASE</version>

</parent>

<name>testboot01</name>

<groupId>com.zuikc</groupId>

<artifactId>testboot01</artifactId>

<version>1.0-SNAPSHOT</version>

<dependencies>

<!--jsp支持, servlet 依赖. -->

<dependency>

<groupId>javax.servlet</groupId>

<artifactId>javax.servlet-api</artifactId>

<scope>provided</scope>

</dependency>

<dependency>

<groupId>javax.servlet</groupId>

<artifactId>jstl</artifactId>

</dependency>

<!-- tomcat 的支持.-->

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-tomcat</artifactId>

</dependency>

<dependency>

<groupId>org.apache.tomcat.embed</groupId>

<artifactId>tomcat-embed-jasper</artifactId>

<scope>provided</scope>

</dependency>

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

</dependency>

<dependency>

<groupId>org.apache.tomcat</groupId>

<artifactId>tomcat-dbcp</artifactId>

<version>7.0.47</version>

</dependency>

<dependency>

<groupId>org.apache.tomcat</groupId>

<artifactId>tomcat-dbcp</artifactId>

<version>7.0.47</version>

</dependency>

<dependency>

<groupId>org.mybatis.spring.boot</groupId>

<artifactId>mybatis-spring-boot-starter</artifactId>

<version>1.3.2</version>

</dependency>

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

</dependencies>

<build>

<plugins>

<plugin>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

</project>

2.配置初始化

首先我们需要将数据库连接配置到文件中，比如prop.properties，

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=utf8

jdbc.username=root

jdbc.password=root

jdbc.maxActive=2335

jdbc.maxIdel=120

jdbc.maxWait=100

然后，用java配置的方式将其引入到代码中，创建DataSourceConfiguration，

package com.zuikc.config;

import org.apache.tomcat.dbcp.dbcp.BasicDataSource;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.PropertySource;

@Configuration

//这个注解导入刚才增加的jdbc配置文件

@PropertySource("classpath:prop.properties")

public class DataSourceConfiguration {

@Value("${jdbc.driver}")

private String driver;

@Value("${jdbc.url}")

private String url;

@Value("${jdbc.username}")

private String username;

@Value("${jdbc.password}")

private String password;

@Value("${jdbc.maxActive}")

private int maxActive;

@Value("${jdbc.maxIdel}")

private int maxIdel;

@Value("${jdbc.maxWait}")

private long maxWait;

@Bean

public BasicDataSource dataSource(){

BasicDataSource dataSource = new BasicDataSource();

dataSource.setDriverClassName(driver);

dataSource.setUrl(url);

dataSource.setUsername(username);

dataSource.setPassword(password);

dataSource.setMaxActive(maxActive);

dataSource.setMaxIdle(maxIdel);

dataSource.setMaxWait(maxWait);

dataSource.setValidationQuery("SELECT 1");

dataSource.setTestOnBorrow(true);

return dataSource;

}

}

接着，增加mybatis配置，

package com.zuikc.config;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;

import org.mybatis.spring.SqlSessionFactoryBean;

import org.mybatis.spring.SqlSessionTemplate;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import org.springframework.transaction.PlatformTransactionManager;

import org.springframework.transaction.annotation.EnableTransactionManagement;

import org.springframework.transaction.annotation.TransactionManagementConfigurer;

@Configuration

//加上这个注解，使得支持事务

@EnableTransactionManagement

public class MyBatisConfig implements TransactionManagementConfigurer {

@Autowired

private DataSource dataSource;

@Override

public PlatformTransactionManager annotationDrivenTransactionManager() {

return new DataSourceTransactionManager(dataSource);

}

@Bean(name = "sqlSessionFactory")

public SqlSessionFactory sqlSessionFactoryBean() {

SqlSessionFactoryBean bean = new SqlSessionFactoryBean();

bean.setDataSource(dataSource);

try {

return bean.getObject();

} catch (Exception e) {

e.printStackTrace();

throw new RuntimeException(e);

}

}

@Bean

public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {

return new SqlSessionTemplate(sqlSessionFactory);

}

}

注意上面的sqlSessionFactory这个bean。

然后需要配置MyBatis配置文件的路径，这个配置需要与上面的配置分开来写，因为它们有着一个先后顺序，

package com.zuikc.config;

import org.mybatis.spring.mapper.MapperScannerConfigurer;

import org.springframework.boot.autoconfigure.AutoConfigureAfter;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

@Configuration

// 因为这个对象的扫描，需要在MyBatisConfig的后面注入，所以加上下面的注解

@AutoConfigureAfter(MyBatisConfig.class)

public class MyBatisMapperScannerConfig {

@Bean

public MapperScannerConfigurer mapperScannerConfigurer() {

MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();

//获取之前注入的beanName为sqlSessionFactory的对象

mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");

//指定xml配置文件的路径

mapperScannerConfigurer.setBasePackage("com.zuikc.dao");

return mapperScannerConfigurer;

}

}

3.三层架构

先创建最底层的dao接口，如下：

package com.zuikc.dao;

import java.util.List;

import java.util.Map;

import org.apache.ibatis.annotations.Mapper;

import org.apache.ibatis.annotations.Select;

@Mapper

public interface TestDao {

@Select("SELECT * FROM tbl_user;")

public List<Map<String,Object>> find();

}

接着创建service，

package com.zuikc.service;

import com.zuikc.dao.TestDao;

import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.List;

import java.util.Map;

@Service

public class TestService {

@Resource

TestDao dao;

public List<Map<String,Object>> find(){

List<Map<String,Object>> users = dao.find();

return users;

}

}

然后是controller，

package com.zuikc.controller;

import com.zuikc.dao.TestDao;

import com.zuikc.service.TestService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import javax.annotation.Resource;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.List;

import java.util.Map;

@Controller

public class StudentController {

@Autowired

TestService service;

@RequestMapping(value = {"test01"})

public String view(Map<String, Object> map) {

List<Map<String,Object>> users = service.find();

for (Map<String, Object> user : users) {

for (Map.Entry<String, Object> entry : user.entrySet()) {

System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());

}

}

System.out.println(users.size());

map.put("name", "zuikc.com");

map.put("date", new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));

return "views/test01";

}

}

经过上面的创建之后，我们的代码结构是这样的，

执行之，

注意了，如果你已经忘记了如何启动MySQL，那么，下面就是命令哦：

sudo bin/mysqld_safe --user=mysql &

4.事务支持

第一步，导入JDBC依赖，

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-jdbc</artifactId>

</dependency>

注意，有了这个依赖，SpringBoot会自动注入DataSourceTransactionManager。

接着，直接在Service中添加@Transactional注解就能支持事务啦。本文不再赘述，大家自己尝试一下吧。

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