使用 Java 开发或者学习过程中，最避免不了的是连接和操作数据库，此次，学习如何在Spring Boot中配置和使用Mybatis框架，提高开发效率。
1、填写pom.xml
<!-- mybatis依赖jar包 --> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> <!-- web项目依赖jar包 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- 热部署依赖jar包 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> </dependency> <!-- mysql连接jar包 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <!-- 阿里巴巴druid数据源 --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.6</version> </dependency>
2、填写application.properties
#数据驱动可配也可以不配，因为系统会自动识别 #spring.datasource.driver-class-name =com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/movie?useUnicode=true&characterEncoding=utf-8 spring.datasource.username =root spring.datasource.password =root #springboot有自带数据源这个也可不配置 spring.datasource.type =com.alibaba.druid.pool.DruidDataSource
#数据驱动可配也可以不配，因为系统会自动识别 #spring.datasource.driver-class-name =com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/movie?useUnicode=true&characterEncoding=utf-8 spring.datasource.username =root spring.datasource.password =root #让控制台打印SQL语句，一般用于本地开发环境 mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl #springboot有自带数据源这个也可不配置 spring.datasource.type =com.alibaba.druid.pool.DruidDataSource
3、User实体
//用户实体 public class User { private int id; private String name; private String phone; private int age; private Date createTime; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } }
4、Springboot主类
//@MapperScan会自动扫描里面的包，而且应该是可以自动给每个类装配一个Bean对象 @SpringBootApplication @MapperScan("com.jincou.mapper") public class MainApplication { public static void main(String[] args) { SpringApplication.run(MainApplication.class, args); } }
5、UserMapper
/** * 功能描述：访问数据库的接口 */ public interface UserMapper { //推荐使用#{}取值，不要用${},因为存在注入的风险 @Insert("INSERT INTO user(name,phone,create_time,age) VALUES(#{name}, #{phone}, #{createTime},#{age})") @Options(useGeneratedKeys=true, keyProperty="id", keyColumn="id") //keyProperty java对象的属性；keyColumn表示数据库的字段 int insert(User user); //column指数据库中的列，property是指实体的属性名，如果一致就不需要写 @Select("SELECT * FROM user") @Results({ @Result(column = "create_time",property = "createTime") }) List<User> getAll(); @Select("SELECT * FROM user WHERE id = #{id}") @Results({ @Result(column = "create_time",property = "createTime") }) User findById(Long id); @Update("UPDATE user SET name=#{name} WHERE id =#{id}") void update(User user); @Delete("DELETE FROM user WHERE id =#{userId}") void delete(Long userId); }
6、UserServise层
public interface UserService { //这里只写了个add方法，其它的直接在控制层调用Dao层，正常开发流程都应该写在Service层 public int add(User user); }
7、UserServiseImpl
@Service public class UserServiceImpl implements UserService{ //因为主类的@MapperScan方法，所以自动为UserMapper装配了一个userMapper对象 @Autowired private UserMapper userMapper; //这里你传过去的时候user的id为null,而insert之后传回回来的user会把数据库中的id值带回来，真强大 @Override public int add(User user) { userMapper.insert(user); int id = user.getId(); return id; } }
8、Controller类
@RestController @RequestMapping("/api/v1/user") public class UserController { //在UserServiceImpl定义了@Service实现类所以可以得到默认首字母小写的对象 @Autowired private UserService userService; @Autowired private UserMapper userMapper; /** * 功能描述: user 保存接口 */ @GetMapping("add") public Object add(){ User user = new User(); user.setAge(11); user.setCreateTime(new Date()); user.setName("张三"); user.setPhone("1880177"); int id = userService.add(user); return id; } /** * 功能描述：查找全部用户 * 这里和下面是直接调用跳过Servise层，直接到DAO层 */ @GetMapping("findAll") public Object findAll(){ return userMapper.getAll(); } /** * 查找单个用户 */ @GetMapping("find_by_id") public Object findById(long id){ return userMapper.findById(id); } /** * 删除单个用户 */ @GetMapping("del_by_id") public Object delById(long id){ userMapper.delete(id); return ""; } /** *更新用户 */ @GetMapping("update") public Object update(String name,int id){ User user = new User(); user.setName(name); user.setId(id); userMapper.update(user); return ""; } }
测试
1.准备好数据库数据：
#Sql脚本 CREATE TABLE `user` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(128) DEFAULT NULL COMMENT '名称', `phone` varchar(16) DEFAULT NULL COMMENT '用户手机号', `create_time` datetime DEFAULT NULL COMMENT '创建时间', `age` int(4) DEFAULT NULL COMMENT '年龄', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=18 DEFAULT CHARSET=utf8;
2测试结果
插入用户，看后台的sql语句
