CREATE TABLE `user` (
  `id` bigint NOT NULL COMMENT '主鍵ID',
  `name` varchar(30) DEFAULT NULL COMMENT '姓名',
  `age` int DEFAULT NULL COMMENT '年齡',
  `email` varchar(50) DEFAULT NULL COMMENT '郵箱',
  PRIMARY KEY (`id`)
)

INSERT INTO `user`(`id`,`name`,`age`,`email`) VALUES
(1,'Jone',18,'test1@baomidou.com'),
(2,'Jack',20,'test2@baomidou.com'),
(3,'Tom',28,'test3@baomidou.com'),
(4,'Sandy',21,'test4@baomidou.com'),
(5,'Billie',24,'test5@baomidou.com');

<!--mp-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.2</version>
</dependency>
<!--mysql-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<!--lombok-->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

#mybatis日志  開啟
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

void findAll() {
    List<User> users = userMapper.selectList(null);
    users.forEach(System.out::println);
}

void addUser(){
    User user = new User(12L, "黎明", 23, "592923@qq.com");
    int insert = userMapper.insert(user); //影響行數(shù)
    System.out.println(insert);
}

public void upData(){
    User user = new User();
    user.setId(12L);
    user.setName("hhha");
    int i = userMapper.updateById(user);
    System.out.println("影響行數(shù)"+i);
}

@TableField(fill = FieldFill.INSERT)
private Data createTime;

@TableField(fill = FieldFill.INSERT_UPDATE)
private Data updateTime;

@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    //實現(xiàn)兩個方法，自動填充增加、修改
}

@Bean
public OptimisticLockerInterceptor optimisticLockerInterceptor() {
    return new OptimisticLockerInterceptor();
}

@Test
public void select1() {
    List<User> users = userMapper.selectBatchIds(Arrays.asList(1, 2, 3));
    for (User user : users) {
        System.out.println(user);
    }
}

public void select2(){
    Map<String, Object> columnMap = new HashMap<>();
    columnMap.put("name", "Jack");
    columnMap.put("age", "20");
    List<User> users = userMapper.selectByMap(columnMap);
    System.out.println(users);
}

public void selectPage() {
    Page<User> page = new Page<>(1,3);
    Page<User> userPage = userMapper.selectPage(page,null);
    long pages = userPage.getPages();//總頁數(shù)
    long current = userPage.getCurrent();//當(dāng)前頁
    List<User> records = userPage.getRecords();//數(shù)據(jù)集合
    long total = userPage.getTotal();
    boolean hasNext = userPage.hasNext();//是否還有下一頁
    boolean previous = userPage.hasPrevious();//上一頁

    System.out.println(pages);
    System.out.println(current);
    System.out.println(records);
    System.out.println(total);
}

public void testWrapper1() {
    /**
     *  ge ：大于等于
     *  gt: 大于
     *  le ： <=
     *  lt ： <
     */
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    QueryWrapper<User> queryWrapper = wrapper.ge("age", 18);
    List<User> users = userMapper.selectList(queryWrapper);
    users.forEach(System.out::println);
}

SELECT id,name,age,email,create_time,update_time,version,deleted FROM user WHERE deleted=0 AND (age >= ?)