用途

1. 可以结合@JpaSelectOperator 使用
2. 可快速的完成单表的复杂查询
   1. 根据入参对象进行查询条件的封装
      1. where field = value and field2 like ‘%value%’ or field3 <> value

用法示例

使用单例构造 SpecificationUtil

• and 为 key写死示例
• and2为根据实体获取key的示例

SpecificationUtil<User> instance = SpecificationUtil.getInstance();
Specification<User> and = instance.like("address", "重庆", true)
    .and(instance.eq("name", "用户", true)
         .or(instance.eq("loginPwd", "123", true))
         .or(instance.eq("phone", "123", true))
         .or(instance.eq("userNo", "123", true))
        );
Specification<User> and2 = instance.like(User::getAddress, "重庆", true)
    .and(instance.eq(User::getName, "用户", true)
         .or(instance.eq(User::getLoginPwd, "123", true))
         .or(instance.eq(User::getPhone, "123", true))
         .or(instance.eq(User::getUserNo, "123", true))
        );
userService.getJpaBasicsDao().findAll(and).forEach(System.out::println);

直接使用 Specification

构建查询条件

public static Specification<User> name() {
    return (root, query, builder) -> builder.like(root.get("name"), "%用户%");
}
public static Specification<User> loginPwd() {
    return (root, query, builder) -> builder.like(root.get("loginPwd"), "123");
}
public static Specification<User> address() {
    return (root, query, builder) -> builder.like(root.get("address"), "重庆");
}
public static Specification<User> phone() {
    return (root, query, builder) -> builder.like(root.get("phone"), "123");
}
public static Specification<User> userNo() {
    return (root, query, builder) -> builder.like(root.get("phone"), "123");
}

使用示例

    userService.getJpaBasicsDao().findAll(
                address().and(
                        loginPwd().or(phone()).or(name())
                ).or(
                        loginPwd().and(
                                phone().or(name())
                        )
                )
        ).forEach(System.out::println);