springboot集成mybatis环境搭建

maven依赖

<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>1.5.5.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> <version>1.5.5.RELEASE</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>6.0.6</version> <scope>runtime</scope> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> </dependencies>

application.yml配置文件

server: port: 9999 logging: level: com.test.mapper: debug #打印sql，这里的路径为mapper包的路径 spring: application: name: mybatis-test datasource: driver: com.mysql.jdbc.Driver url: jdbc:mysql://192.168.1.250:3306/mybatis-test?useSSL=false&useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&useInformationSchema=true&autoReconnect=true&failOverReadOnly=false username: root password: 1234 mybatis: mapper-locations: classpath:mapping/*Mapper.xml #使用mapper配置文件时必须要配置，如果使用mybatis注解的话此配置不需要

创建实体类

/** * 这里用到了@Data注解，需要引入lombok包 */ @Data public class User implements Serializable { private Long id; private String userName; private String password; }

创建mapper类

这里的mapper类必须和配置文件打印sql日志的包一致，即com.test.mapper。

只要使用@Mapper注解后，在系统启动后，会为该接口使用动态代理的方式生成实现类

/** * 如果参数有多个，需要用@Param注解标识出来 */ @Mapper public interface UserMapper { int insert(User user); int update(User user); List<User> findAll(); int delete(Long id); List<User> find(@Param("uname")String userName,@Param("pwd")String password); }

mapper文件

mapper文件的路径需要和application配置文件中的mapper文件定义保持一致

<?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"> <!--namespace参数为对应的mapper类的全路径--> <mapper namespace="com.msxf.activity.test.mapper.UserMapper"> <!--resultMap定义数据库表字段和Java对象属性映射关系，如果是多表操作或者数据库字段和Java属性字段不一致时必须配置--> <resultMap id="userMap" type="com.msxf.activity.test.enty.User"> <id column="id" property="id"/> <result column="user_name" property="userName"/> <result column="password" property="password"/> </resultMap> <insert id="insert" parameterType="com.msxf.activity.test.enty.User"> insert into user(user_name,password) values (#{userName},#{password}) </insert> <update id="update" parameterType="com.msxf.activity.test.enty.User"> update user set user_name = #{userName},password = #{password} where id = #{id} </update> <delete id="delete" parameterType="long"> delete from user where id = #{id} </delete> <select id="findAll" resultMap="userMap"> select * from user </select> <select id="find" resultMap="userMap"> <!--#{uname}必须和mapper类中的注解@Param参数一致--> select * from user where user_name=#{uname} and password=#{pwd} </select> </mapper>

service controller类

@Service @Transactional public class UserService { //这里建议用resource，如果用@Autowired注入，idea会报找不到对应的bean的错 @Resource private UserMapper userMapper; public int insert(User user){ return userMapper.insert(user); } public int update(User user){ return userMapper.update(user); } public int delete(Long id){ return userMapper.delete(id); } public List<User> findAll(){ return userMapper.findAll(); } } @RestController @RequestMapping("/user") public class UserController { @Resource private UserService userService; @RequestMapping("insert") public ResponseData insertUser(@RequestBody User user){ ResponseData result = new ResponseData(); int insert = userService.insert(user); result.setData(insert); return result; } @RequestMapping("update") public ResponseData updateUser(@RequestBody User user){ ResponseData result = new ResponseData(); int update = userService.update(user); result.setData(update); return result; } @RequestMapping("delete") public ResponseData deleteUser(@RequestParam("id") Long id){ ResponseData result = new ResponseData(); int delete = userService.delete(id); result.setData(delete); return result; } @RequestMapping("findAll") public ResponseData findAllUser(){ ResponseData result = new ResponseData(); List<User> all = userService.findAll(); result.setData(all); return result; } }

springboot启动类

@SpringBootApplication @MapperScan("com.test.mybatis") @EnableSwagger2 public class App { public static void main(String[] args) { SpringApplication.run(App.class, args); } }

基于注解的mapper类

注解有如下2种：

在mapper类的方法上使用@insert、@update、@select、@delete 优点：简单方便缺点：sql语句需要动态拼接时无法实现 在mapper类的方法上使用@InsertProvider、@UpdateProvider、@SelectProvider和@DeleteProvider 优点：可动态拼接sql语句，甚至比xml文件更灵活缺点：稍微不第一种方式复杂点

注意：这2种方式只是在组装sql时才有差别，其他的完全一致，即在@select中写完sql，还可以在下面写@Results，而使用@SelectProvider后 还是可以在下面继续使用注解@Results

在mapper类的方法上直接写sql

@Mapper public interface UserMapper { @Insert("insert into user(user_name,password) values (#{userName},#{password})") int insert(User user); @Update("update user set user_name = #{userName},password = #{password} where id = #{id}") int update(User user); @Select({"select * from user",}) @Results(id = "userMap",value = { @Result(column = "user_name",property = "userName"), @Result(column = "password",property = "password") }) List<User> findAll(); @Delete("delete from user where id = #{id}") int delete(Long id); }

在mapper类的方法上指定sql语句拼接类，在类中实现sql语句的编写

需求：将客户端请求过来的数据保存到一个表中，请求数据会指明数据应该保存到哪个表中，请求的数据可能是表中字段的一个子集， 请求格式为：{“datas”:{“user_name”:“zhangsan”,“password”:“123456”},“tableName”:“t_user”}

@Mapper public interface MyEntityMapper { @InsertProvider(type = MyEntityProvider.class, method = "save") @Options(keyColumn = "id", useGeneratedKeys = true) void save(MyEntity entity); @UpdateProvider(type = MyEntityProvider.class,method = "update") int update(MyEntity entity); @SelectProvider(type = MyEntityProvider.class,method = "findOne") Map<String,Object> findOne(MyEntity entity); @SelectProvider(type = MyEntityProvider.class,method = "findAll") List<MyEntity> findAll(MyEntity entity); //有多个参数时，需要使用@Param注解 @SelectProvider(type = MyEntityProvider.class,method = "findByUserNameAndPassword") MyEntity findByUserNameAndPassword(@Param("uname")String userName,@Param("pwd") String password); } //MyEntityProvider.java public class MyEntityProvider { public String save(MyEntity entity){ SQL sql = new SQL(); sql.INSERT_INTO(entity.getTableName());//组装 insert into tableName String [] fileds = new String[entity.getDatas().size()]; String [] values = new String[entity.getDatas().size()]; int i=0; //key为数据库字段 value为要保存的值 Map<String, Object> fieldAndValues = entity.getDatas(); Iterator<Map.Entry<String, Object>> it = fieldAndValues.entrySet().iterator(); while(it.hasNext()){ Map.Entry<String, Object> next = it.next(); String key = next.getKey(); fileds[i] = key; values[i] = "#{datas."+key+"}"; i++; } sql.INTO_COLUMNS(fileds); //组装tableName后的字段列表 sql.INTO_VALUES(values); //组装values后的占位符 return sql.toString(); } public String update(MyEntity entity){ SQL sql = new SQL(); sql.UPDATE(entity.getTableName()); //组装update tableName Map<String, Object> fieldAndValues = entity.getDatas(); Iterator<Map.Entry<String, Object>> it = fieldAndValues.entrySet().iterator(); while(it.hasNext()){ Map.Entry<String, Object> next = it.next(); String key = next.getKey(); String values = "#{datas."+key+"}"; String set = key+"="+values; sql.SET(set);//动态拼接 set xx=yy } sql.WHERE("id=#{datas.id}");//拼接where后的条件 return sql.toString(); } public String findOne(MyEntity entity){ SQL sql = new SQL(); sql.SELECT("*");//select * sql.FROM(entity.getTableName());//from tableName sql.WHERE("id=#{datas.id}");//where return sql.toString(); } //注意，这里一定要使用@param注解，不然会报找不到字段的异常 public String findByUserNameAndPassword(@Param("uname")String userName,@Param("pwd") String password){ SQL sql = new SQL(); sql.SELECT("*"); sql.FROM(entity.getTableName()); sql.WHERE("user_name=${uname} and password=${pwd}"); return sql.toString(); } }

注意，如果使用基于注解的mapper的话，需要注意如下2点：

在application.yaml的配置文件中，不需要mybatis.mapper-locations=classpath:mapping/*Mapper.xml配置在springboot启动类中，需要添加@MapperScan(“mapper包名”)，指引spring加载对应的mapper类，当然如果启动类所在的包在mapper包外的话，可以不用指定

一个最简单的springboot+mybatis的整合就完成了。