创建实体类省略【get方法，set方法，构造方法】
<!--简化bean代码的工具包-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
<version>1.18.4</version>
</dependency>
实体类
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private Long id;
private String userName;
private String password;
private String name;
private Integer age;
private String email;
}
mp整合mybatis
- UserMapper.java接口继承BaseMapper<T>：就可以使用BaseMapper<T>中的方法
public interface UserMapper extends BaseMapper<User> { List<User> findAll(); } - 实体类用的哪个表
@TableName("tb_user")
public class User {
private Long id;
private String userName;
private String password;
private String name;
private Integer age;
private String email;
}
- 使用mp提供的MybatisSqlSessionFactoryBuilder构建工厂创建SqlSessionFactory，此时就可以使用BaseMapper中的方法
public class TestMybatis {
@Test
public void testFindAll(){
try {
InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sessionFactory = new MybatisSqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sessionFactory.openSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
//List<User> all = mapper.findAll();
List<User> all = mapper.selectList(null);
for (User user:all) {
System.out.println(user);
}
sqlSession.commit();
sqlSession.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
mp，mybatis，spring整合
pom
<properties>
<spring.version>5.1.6.RELEASE</spring.version>
</properties>
<!--spring相关-->
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
applicationContext
<context:property-placeholder location="classpath:*.properties"/>
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
<property name="driverClassName" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</bean>
<bean id="sqlSessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation" value="classpath:mybatis-config.xml"/><!--可以不写 mybatis核心文件-->
</bean>
<!--扫描mapper所在的包 为mapper创建实现类-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.xjbt.mapper"></property>
</bean>
test
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class TestMybatis {
@Autowired
private UserMapper userMapper;
@Test
public void testFindAll() {
List<User> all = userMapper.selectList(null);
for (User user : all) {
System.out.println(user);
}
}
}
springboot mybatis mp整合
pom
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.4.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--简化代码的工具包-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
<version>1.18.20</version>
</dependency>
<!--mybatis-plus的springboot支持-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.1.1</version>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
MyApplication主文件
@MapperScan("com.xjbt.mapper")
@SpringBootApplication
public class MyApplication {
public static void main(String[] args) {
SpringApplication.run(MyApplication.class, args);
}
}
application.properties
spring.application.name = springbootmybatis_plusmybatis
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mp?useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
测试
mp 通用crud操作
实体类注解
@Data //get set toStrong...
@NoArgsConstructor //无参构造
@AllArgsConstructor //有参构造
//下边都是mybatis-plus注解
@TableName("tb_user") //使用那张数据表
public class User {
@TableId(type = IdType.AUTO) //自增
private Long id;
//1，字段名称和属性名不一致使用
@TableField("user_name")
private String user;
//2,属性在数据库中不存在
@TableField(exist = false)
private String addr;
//3,字段不加入查询字段
@TableField(select = false)
private String password;
private String name;
private Integer age;
private String email;
}
1. 插入操作：
int insert(T entity); 返回发生变化的记录行数
@Test
public void testInsert() {
User user=new User();
user.setUserName("dd");
user.setPassword("123");
userMapper.insert(user);
System.out.println(user);
System.out.println("id=>"+user.getId());//自增后的id会回填到对象中
}
设置id生成策略：@IdType
@Getter
public enum IdType {
AUTO(0) =>数据库id自增长
NONE(1) =>该类型为未设置主键类型
INPUT(2) =>用户输入ID
========以下3种类型、只有当插入对象ID 为空，才自动填充。 =========
ID_WORKER(3),=>全局唯一ID[idWorker]
UUID(4) =>全局唯一ID[UUID]
ID_WORKER_STR(5) =>字符串全局唯一ID (idWorker 的字符串表示)
2. 更新操作：
- 根据id：
int updateById(@Param(Constants.ENTITY) T entity)@Test public void testUpdate(){ User user=new User(); user.setId(8L); user.setAge(12); userMapper.updateById(user); } - 根据条件更新:
int update(@Param(Constants.ENTITY) T entity, @Param(Constants.WRAPPER) Wrapper<T> updateWrapper);/** * QueryWrapper */ @Test public void testUpdate(){ //UPDATE tb_user SET age=? WHERE age=? AND user_name = ? User user=new User(); user.setAge(21);//set更新 QueryWrapper<User> userQueryWrapper = new QueryWrapper<>(user); userQueryWrapper.eq("user_name","张三");//where条件 userMapper.update(user,userQueryWrapper); } /** * UpdateWrapper */ @Test public void testUpdate2(){ //UPDATE tb_user SET age=?,user_name=? WHERE user_name = ? User user=new User(); UpdateWrapper<User> userUpdateWrapper = new UpdateWrapper<>(user); userUpdateWrapper.set("age",22).set("user_name","admin"); userUpdateWrapper.eq("user_name","zhangsan"); userMapper.update(null,userUpdateWrapper); }
3. 删除操作：
- 根据id：
int deleteById(Serializable id);@Test public void testDeleteById() { int result = this.userMapper.deleteById(6L); } - 多条件查询：
int deleteByMap(@Param(Constants.COLUMN_MAP) Map<String, Object> columnMap);@Test public void testDeleteMap(){ Map<String,Object> hashMap=new HashMap<String,Object>(); hashMap.put("User_name","dd"); hashMap.put("age",null); userMapper.deleteByMap(hashMap); } - 根据实体类对象：
int delete(@Param(Constants.WRAPPER) Wrapper<T> wrapper);@Test public void testDeleteByEnty() { User user=new User(); //1[推荐]面向对象 不用写字段 user.setUser("dd"); user.setAge(12); QueryWrapper<User> userQueryWrapper =new QueryWrapper<User>(user); userMapper.delete(userQueryWrapper); //2 /* QueryWrapper<User> userQueryWrapper = new QueryWrapper<>(); userQueryWrapper.eq("user_name","dd").eq("age",null); userMapper.delete(userQueryWrapper);*/ }
4.批量删除：int deleteBatchIds(@Param(Constants.COLLECTION) Collection<? extends Serializable> idList);
@Test
public void testDeleteBatchIds() {
userMapper.deleteBatchIds(Arrays.asList(9,10));
}
5. 查询：
- 通过id查询：
T selectById(Serializable id);@Test public void testSelectById() { User user = userMapper.selectById(1); System.out.println(user); } - 根据id批量查询：
List<T> selectBatchIds(@Param(Constants.COLLECTION) Collection<? extends Serializable> idList);@Test public void testSelectBatchIds() { List<User> userList = userMapper.selectBatchIds(Arrays.asList(1, 2, 3, 4, 5)); System.out.println(userList); } - 根据条件查询一条数据：
T selectOne(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);@Test public void testSelectOne() { QueryWrapper<User> userQueryWrapper = new QueryWrapper<>(); userQueryWrapper.eq("user_name","admin"); User user = userMapper.selectOne(userQueryWrapper); } - 根据 Wrapper 条件，查询总记录数:
Integer selectCount(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);@Test public void testSelectCount() { QueryWrapper<User> userQueryWrapper = new QueryWrapper<>(); userQueryWrapper.gt("age","20"); int userCount = userMapper.selectCount(userQueryWrapper); System.out.println(userCount); } - 根据 entity 条件，查询全部记录：
List<T> selectList(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);@Test public void testSelectList() { QueryWrapper queryWrapper = new QueryWrapper(); queryWrapper.like("email","it"); List list = userMapper.selectList(queryWrapper); System.out.println(list); } - 分页查询：
IPage<T> selectPage(IPage<T> page, @Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
配置类
分页测试@Configuration @MapperScan("com.xjbt.mapper") public class MyBatisplusPage { @Bean //配置分页插件 public PaginationInterceptor paginationInterceptor(){//拦截器 return new PaginationInterceptor(); }//分页测试 @Test public void testIpage(){ Page<User> page = new Page<User>(1,1); QueryWrapper queryWrapper=new QueryWrapper(); queryWrapper.like("email","it"); IPage iPage = userMapper.selectPage(page, queryWrapper); System.out.println("总条数"+iPage.getTotal()); System.out.println("总页数"+iPage.getPages()); System.out.println("当前页"+iPage.getCurrent()); List<User> records = iPage.getRecords(); for (User user:records) { System.out.println(user); } }
mybatis-plus基本配置
-
springbooot【配置文件application.prooerties】
mybatis-plus.configuration和mybatis-plus.config-location不能同时存在
- 指定全局的配置文件
mybatis-plus.config-location=classpath:mybatis-config.xml - 指定mapper【可以写自己定义的方法】
mybatis-plus.mapper-locations = classpath*:mybatis/*.xml - 实体对象的扫描包 给实体类起别名
mybatis-plus.type-aliases-package=com.xjbt.pojo - 禁用自动驼峰映射【字段user_name可写成userName】
全局地开启或关闭配置文件中的所有映射器已经配置的任何缓存，默认为 true。不能和第一项一起使用，第一项的意思是使用mybatis核心配置文件，mybatis默认禁用驼峰命名和这个禁用起冲突 mybatis-plus.configuration.map-underscore-to-camel-case=false
全局默认主键类型，设置后，即可省略实体对象中的@TableId(type = IdType.AUTO)配置。mybatis-plus.configuration.cache-enabled=false
表名前缀，全局配置后可省略@TableName()配置。mybatis-plus.global-config.db-config.id-type=automybatis-plus.global-config.db-config.table-prefix=tb_
- 指定全局的配置文件
-
ssm【配置文件applicationContext.xml】
- 指定全局的配置文件
<bean id="sqlSessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"> =>指定全局的配置文件dataSource <property name="dataSource" ref="dataSource" /> =>指定全局的配置文件 <property name="configLocation" value="classpath:mybatis-config.xml"/> =>指定mapper 可以定义方法 <property name="mapperLocations" value="classpath:UserMapper.xml"/> =>给实体类起别名 <property name="typeAliasesPackage" value="com.xjbt.pojo"/> <bean class="com.baomidou.mybatisplus.core.config.GlobalConfig"> <property name="dbConfig"> --=> 全局默认主键类型，设置后，即可省略实体对象中的@TableId(type = IdType.AUTO)配置。--> <bean class="com.baomidou.mybatisplus.core.config.GlobalConfig$DbConfig"> <property name="idType" value="AUTO"/> => 表名前缀，全局配置后可省略@TableName()配置。--> <property name="tablePrefix" value="tb_"/> </bean> </property> </bean> </bean>
- 指定全局的配置文件
条件构造器【可去官网：https://baomidou.com/pages/10c804/#having有完整的示例】
allEq：
@Test
public void testSelectAllEq() {
Map<String,Object> map=new HashMap<>();
map.put("name","张三");
map.put("age",22);
map.put("password","123456");
QueryWrapper<User> queryWrapper=new QueryWrapper<>();
// SELECT id,user_name AS user,name,age,email FROM tb_user WHERE password = ? AND name = ? AND age = ?
queryWrapper.allEq(map);
// SELECT id,user_name AS user,name,age,email FROM tb_user WHERE password = ? AND name = ?
queryWrapper.allEq(map,false)忽略条件中vlaue是null的
查询key中包含"g"的key
// SELECT id,user_name AS user,name,age,email FROM tb_user WHERE age = ?
queryWrapper.allEq((k,v) -> k.contains("g"),map);
userMapper.selectList(queryWrapper);
}
ActiveRecord【AR】
定义：
ActiveRecord也属于ORM（对象关系映射）层，由Rails最早提出。
遵循标准的ORM模型：表映射到记录【一行数据】，记录映射到对象，字段映射到对象属性。配合遵循的命名和配置惯例，能够很大程度的快速实现模型的操作，而且简洁易懂。
ActiveRecord的主要思想是：
- 表对应类，类中的属性对应了表中的字段，类的实例化对应表中的数据
- ActiveRecord同时负责把自己持久化，在ActiveRecord中封装了对数据库的访问，即CURD;
- ActiveRecord是一种领域模型(Domain Model)，封装了部分业务逻辑；
使用AR
实体类继承Model<T>
public class User extends Model<User>
测试：
@Test
public void testAR(){
User user = new User();
user.setId(2L);
User user2 = user.selectById();
System.out.println(user2);
}
方法和mybatis方法一样。
mybatis插件机制：
MyBatis 允许你在已映射语句执行过程中的某一点进行拦截调用。默认情况下，MyBatis 允许使用插件来拦截的方法
调用包括：
1. Executor (update, query, flushStatements, commit, rollback, getTransaction, close, isClosed)【1. 拦截执行器的方法】
2. ParameterHandler (getParameterObject, setParameters)【2. 拦截参数的处理】
3. ResultSetHandler (handleResultSets, handleOutputParameters)【3. 拦截结果集的处理】
4. StatementHandler (prepare, parameterize, batch, update, query)【4. 拦截Sql语法构建的处理】
