枚举的优越性不用多说。在实体中使用,上代码
实体类:
@Entity @Table(name = "cache_user") public class User { /** * 用户类型 */ public static enum AccountType { TEACHER,//老师 STUDENT;//学生 } @Id @GenericGenerator(name = "uuid", strategy = "uuid2") @GeneratedValue(generator = "uuid") private String id; private String name; private int age; /** * EnumType: ORDINAL 枚举序数 默认选项(int)。eg:TEACHER 数据库存储的是 0 * STRING:枚举名称 (String)。eg:TEACHER 数据库存储的是 "TEACHER" */ @Enumerated(EnumType.STRING) private AccountType accountType = AccountType.TEACHER; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public User() { super(); } public AccountType getAccountType() { return accountType; } public void setAccountType(AccountType accountType) { this.accountType = accountType; }
查询时:
@Query("from User u where u.accountType = :type ")
User findByType(@Param("type") AccountType type);
eg :
User u3 = userRepository.findByType(AccountType.TEACHER);
System.out.println("第二次查询:" + u3.getAge());
生成的sql:
INFO [main] jdbc.sqlonly.sqlOccured:226 - select user0_.id as id1_0_, user0_.account_type as account_2_0_, user0_.age as age3_0_, user0_.name as name4_0_ from cache_user user0_ where user0_.account_type='KEEPER'
如果注解是:
@Enumerated(EnumType.ORDINAL) private AccountType accountType = AccountType.TEACHER;
或者无注解:
private AccountType accountType = AccountType.TEACHER;
生成的sql:
[main] jdbc.sqltiming.sqlTimingOccured:370 - select user0_.id as id1_0_, user0_.account_type as account_2_0_, user0_.age as age3_0_, user0_.name
as name4_0_ from cache_user user0_ where user0_.account_type=0