[Spring]常用註解和技術彙總

註解

常用註解

@Valid    //使用hibernate validation的時候使用

@Validated //用spring  Validator 校驗機制使用

@Entity     //實體類

@Table(name=" 表名")  

@Id  // 主鍵

@Pattern(regexp = "([a-z0-9A-Z]+[-|\\.]?)+[a-z0-9A-Z]@([a-z0-9A-Z]+(-[a-z0-9A-Z]+)?\\.)+[a-zA-Z]{2,}", message = "郵箱錯誤")

@NotNull(message = "不能爲空")

@NotBlank   //檢查約束字符串是不是Null，最少一個非空白字符.

@Size(min=, max=) 驗證對象（Array,Collection,Map,String）長度是否在給定的範圍之內 

@EnableTransactionManagement  // 啓註解事務管理，等同於xml配置方式的 <tx:annotation-driven />

@MapperScan(basePackages = "com.test.dao", markerInterface = MyMapper.class)


// 加載properties中的配置
@ConfigurationProperties("test")
@Component
@PropertySource("classpath:test.properties")

緩存註解

@EnableCaching
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)


    @ConditionalOnMissingBean(name = "redisTemplate")


 

緩存註解的文章 https://blog.csdn.net/dreamhai/article/details/80642010

主鍵註解生成策略

主鍵生成策略
//生成32位UUID 不是標準的uuid而是去掉橫槓的

  		@GenericGenerator(name = "idGenerator", strategy = "uuid") 
        @GeneratedValue(generator = "idGenerator")

//完整寫法
	@GenericGenerator(name = "idGenerator", strategy = "org.hibernate.id.UUIDGenerator")
    @GeneratedValue(generator = "idGenerator")

常用的時間註解

該註解被insert 時會被觸發

@CreatedDate   創建時間
@CreatedBy   創建人
@LastModifiedDate
@LastModifiedBy

使用方法

1. 在啓動類上添加 @EnableJpaAuditing
2. 在entity類上添加 @EntityListeners(AuditingEntityListener.class)
3. 在字段上添加 @CreatedDate

查詢

// 繼承接口
public interface **Repository extends JpaRepository<PjPrj, String>, JpaSpecificationExecutor {
}

關聯關係

一對一

// 一個人只養一隻狗

// Person
 	@OneToOne(targetEntity = Dog.class, cascade = CascadeType.PERSIST)
 	
    @JoinColumn(name = "dogid", referencedColumnName = "id")
    private Dog dog;

//Dog

person 表中就會將dog的id主鍵作爲外鍵進行關聯，完成一對一的關聯關係

一對多

多對多

條件查詢

  @Override
    public Page queryAll(PjPrj resources, Pageable pageable, String time) {

        Page all = pjPrjRepository.findAll(new Specification() {

            @Override
            public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder criteriaBuilder) {
                List<Predicate> list = new ArrayList<Predicate>();
                //todo 條件查詢

                if (!ObjectUtils.isEmpty(resources.getPjn())) {
                    list.add(criteriaBuilder.equal(root.get("pjn"), resources.getPjn()));
                }

                if (!ObjectUtils.isEmpty(time)) {
                    String[] split = time.split(",");

                    SimpleDateFormat sdfmat = new SimpleDateFormat("yyyy-MM-dd");
                    try {

                        list.add(criteriaBuilder.between(root.get("createtime"),
                                sdfmat.parse(split[0]),
                                sdfmat.parse(split[1])));
                    } catch (ParseException e) {
                        e.printStackTrace();
                    }
                }

                Predicate[] p = new Predicate[list.size()];
                return criteriaBuilder.and(list.toArray(p));
            }
        }, pageable);

        return all;
    }

數據庫配置

 #配置 Jpa
 spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: root
 


  #配置 Jpa
  jpa:
    properties:
      hibernate:
        dialect: org.hibernate.dialect.MySQL5InnoDBDialect
    #        format_sql: true # 格式化 生成的sql
    open-in-view: true
  #    show-sql: true  # 顯示sql語句