SpringBootMVC04——Mybatis
简介
MyBatis是一个优秀的持久层框架，它对jdbc的操作数据库的过程进行封装，使开发者只需要关注SQL本身，而不需要花费精力去处理例如注册驱动、创建connection、创建statement、手动设置参数、
结果集检索等jdbc繁杂的过程代码。
配置文件
MybatisConfig.xml
SSM中需要配置
数据url
数据库连接池
映射文件
事务
在SpringBoot中整合到property中了
Mapper.xml
namespace 接口绑定 和接口 就可以不用写DAO实现类，Mybatis会通过绑定自动找到要执行的sql语句。 resultMap 结果集对应到实体类的字段到属性映射
xml 方式
传统方式
xml配置
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <!-- version: $Id$ --> <configuration> <!-- 引用JDBC属性的配置文件 --> <properties resource="database.properties" /> <environments default="development"> <environment id="development"> <!-- 使用JDBC的事务管理 --> <transactionManager type="JDBC" /> <!-- POOLED ：JDBC连接对象的数据源连接池的实现，不直接支持第三方数据库连接池 --> <dataSource type="POOLED"> <property name="driver" value="${database.driver}" /> <property name="url" value="${database.url}" /> <property name="username" value="${database.username}" /> <property name="password" value="${database.password}" /> </dataSource> </environment> </environments> <!-- ORM映射文件 --> <mappers> <!-- 注解的方式 --> <mapper class="com.iflytek.dao.mapper.AccountMapper" /> <!-- XML的方式 --> <mapper resource="com/mashibing/dao/xml/AccountMapper.xml" /> <!-- 这里对于注解，还可以通过<package name="com.mashibing.dao.mapper"/> --> </mappers> </configuration>
Service 配置
public class AccountService { public boolean insertAccount(Account account) { boolean flag = false; SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession(); try { accountMapper accountMapper = sqlSession.getMapper(AccountMapper.class); int result = accountMapper.insert(student); if (result > 0) { flag = true; } sqlSession.commit(); } finally { sqlSession.close(); } return flag; } public Student getAccountById(int id) { SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession(); try { AccountMapper AccountMapper = sqlSession.getMapper(AccountMapper.class); return AccountMapper.selectByPrimaryKey(id); } finally { sqlSession.close(); } } public List<Student> getAllStudents() { SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession(); try { StudentMapper StudentMapper = sqlSession.getMapper(StudentMapper.class); return StudentMapper.selectByExample(new StudentExample()); } finally { sqlSession.close(); } } public boolean updateAccount(Account account) { SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession(); boolean flag = false; try { AccountMapper AccountMapper = sqlSession.getMapper(AccountMapper.class); int result = AccountMapper.updateByPrimaryKey(Account); if (result > 0) { flag = true; } sqlSession.commit(); } finally { sqlSession.close(); } return flag; } public boolean deleteAccount(int id) { SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession(); boolean flag = false; try { AccountMapper AccountMapper = sqlSession.getMapper(AccountMapper.class); int result = AccountMapper.deleteByPrimaryKey(id); if (result > 0) { flag = true; } sqlSession.commit(); } finally { sqlSession.close(); } return flag; } }
与SpringBoot整合
引入依赖
<?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> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.6.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.example</groupId> <artifactId>springboot03-mybatis</artifactId> <version>0.0.1-SNAPSHOT</version> <name>springboot03-mybatis</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <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>2.0.1</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.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
mapper
<?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.mashibing.springboot.mapper.AccountMapper"> <resultMap type="com.mashibing.springboot.mapper.Account" id="BaseResultMap"> <result column="login_name" property="loginName"/> <result column="password" property="password"/> </resultMap> <insert id="save" parameterType="Account"> INSERT INTO account(login_name,password) VALUES ( #{loginName},#{password} ) </insert> <select id="findAll" resultMap="BaseResultMap"> select * from account </select> </mapper>
application.properties
spring.datasource.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=utf8&useSSL=false&serverTimezone=UTC ##数据库用户名 spring.datasource.username=root ##数据库密码 spring.datasource.password=840416 # 用来实例化mapper接口 mybatis.type-aliases-package=com.mashibing.springboot.mapper # 对应的sql映射 mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
AccountMapper
package com.mashibing.springboot.mapper; import org.apache.ibatis.annotations.Mapper; @Mapper public interface AccountMapper { void save(Account account); }
Account
public class Account { private int id; private String loginName; private String password; private String nickName; private int age; private String location; private int banlance; public int getId() {
显示日志
logging.level.com.mashibing.springboot.mapper=debug
注解查询
@Select("select * from account1") List<Account> findAll();
查找mapper接口
在入口加入 MapperScan
@MapperScan("com.mashibing.springboot.mapper") public class Springboot03MybatisApplication {
每一个mapper接口上加入
@Mapper public interface AccountMapper {
Mapper 自动生成
eclipse插件 市场搜素
MyBatis Generator
图形化
https://github.com/zouzg/mybatis-generator-gui
分页查询
依赖
<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper-spring-boot-starter --> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper-spring-boot-starter</artifactId> <version>1.2.12</version> </dependency>
Service
public Object findPage(int pageNum, int pageSize) { PageHelper.startPage(pageNum, pageSize); AccountExample example = new AccountExample(); return mapper.selectByExample(example ); }
