通用mapper _通用mapper

万事须己运，他得非我贤。这篇文章主要讲述通用mapper相关的知识，希望能为你提供帮助。

< !--通用mapper依赖--> < !--< dependency> --> < !--< groupId> tk.mybatis< /groupId> --> < !--< artifactId> mapper-spring-boot-starter< /artifactId> --> < !--< version> 2.1.5< /version> --> < !--< /dependency> -->

实体user：

@Table(name="user") // 配置实体映射的表名 public class User implements Serializable { private static final long serialVersionUID = -37900582537861695L; @Id // 必须配置不配置，如果使用通过ID查询的时候会把所有字段当作条件进行查询 private Integer id; private String userName; private String address; public String getUserName() { return userName; }public void setUserName(String userName) { this.userName = userName; }public String getAddress() { return address; }public void setAddress(String address) { this.address = address; }public Integer getId() { return id; }public void setId(Integer id) { this.id = id; } }

mapper：

@Component @org.apache.ibatis.annotations.Mapper public interface UserMapper extends Mapper< User> {}

测试test：

public class MapperTest extends ApplicationTests { @Autowired private UserMapper userMapper; ///////////////////////// 查询测试 ///////////////////// // 测试根据ID查询，必须在注解字段标记@Id @Test public void testSelectById() throws Exception { List< User> users = userMapper.selectAll(); convertToJson(users); }// 测试根据指定的列进行查询 @Test public void testSelectByColumns() throws Exception { // 创建查询条件对象 Example example = new Example(User.class); example.and().andEqualTo("userName","admin") .andEqualTo("address","广州"); /* Example.Criteria criteria = example.createCriteria(); criteria.andEqualTo("userName","牧*人") .andEqualTo("updateTime","2020-04-21 23:42:13.0"); */ User user = userMapper.selectOneByExample(example); convertToJson(user); }