分佈式01-Spring boot 快速搭建開發

Spring Boot是由Pivotal團隊提供的全新框架，其設計目的是用來簡化新Spring應用的初始搭建以及開發過程。該框架使用了特定的方式來進行配置，從而使開發人員再也不須要定義樣板化的配置。經過這種方式，Spring Boot致力於在蓬勃發展的快速應用開發領域(rapid application development)成爲領導者。

進入https://start.spring.io/

 

Gradle配置

compile("org.springframework.boot:spring-boot-starter-data-jpa")

compile("mysql:mysql-connector-java")

application.properties 配置：

spring.datasource.url = jdbc:mysql://localhost:3306/test

spring.datasource.username = root

spring.datasource.password = root

spring.datasource.driverClassName = com.mysql.jdbc.Driver

spring.jpa.database = MYSQL

spring.jpa.show-sql = true

# 是否自動建立表和字段

spring.jpa.hibernate.ddl-auto = update

spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy

spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

 

建立實體類

@Table(name = "role", uniqueConstraints = { @UniqueConstraint(columnNames = { "name", "shopId" }) })

 

建立實體類Repository

 

測試：

 

Repository使用

根據email地址和姓查詢數據

List<Person> findByEmailAddressAndLastname(EmailAddress emailAddress, String lastname);

使用page作分頁（重點好用切記切記）

本身聲明 Pageable對象

Pageable pageable = new PageRequest(PageNumber(), PageSize(), Sort.Direction.ASC,"排序字段");

在controller用參數傳入：

Page<User> queryFirst10ByLastname(String lastname, Pageable pageable);

根據age字段倒敘

User findTopByOrderByAgeDesc();

用HQL查詢

@Query("select u from User u where u.emailAddress = ?1")User findByEmailAddress(String emailAddress);

使用本地sql語句查詢。nativeQuery = true

@Query(value = "SELECT * FROM USERS WHERE EMAIL_ADDRESS = :emailAddress", 

nativeQuery = true)  User findByEmailAddress(@Param("emailAddress") String emailAddress);

Keyword	Sample	JPQL snippet
And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Is,Equals	findByFirstname,findByFirstnameIs,findByFirstnameEquals	… where x.firstname = ?1
Between	findByStartDateBetween	… where x.startDate between ?1 and ?2
LessThan	findByAgeLessThan	… where x.age < ?1
LessThanEqual	findByAgeLessThanEqual	… where x.age ⇐ ?1
GreaterThan	findByAgeGreaterThan	… where x.age > ?1
GreaterThanEqual	findByAgeGreaterThanEqual	… where x.age >= ?1
After	findByStartDateAfter	… where x.startDate > ?1
Before	findByStartDateBefore	… where x.startDate < ?1
IsNull	findByAgeIsNull	… where x.age is null
IsNotNull,NotNull	findByAge(Is)NotNull	… where x.age not null
Like	findByFirstnameLike	… where x.firstname like ?1
NotLike	findByFirstnameNotLike	… where x.firstname not like ?1
StartingWith	findByFirstnameStartingWith	… where x.firstname like ?1 (parameter bound with appended %)
EndingWith	findByFirstnameEndingWith	… where x.firstname like ?1 (parameter bound with prepended %)
Containing	findByFirstnameContaining	… where x.firstname like ?1 (parameter bound wrapped in %)
OrderBy	findByAgeOrderByLastnameDesc	… where x.age = ?1 order by x.lastname desc
Not	findByLastnameNot	… where x.lastname <> ?1
In	findByAgeIn(Collection ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection age)	… where x.age not in ?1
True	findByActiveTrue()	… where x.active = true
False	findByActiveFalse()	… where x.active = false
IgnoreCase	findByFirstnameIgnoreCase	… where UPPER(x.firstame) = UPPER(?1)

缺點：

JPA 每次查詢都是整個對象查詢，也就是查詢表的全部字段（比select * 性能好）若是是單獨查詢某寫字段，JPA的是用數組返回。相對mybatis這個就很不方便。若是對select 出來的字段又嚴格要求，謹慎使用。

使用JPA的時候，儘可能把表字段分散，別在一張表放太多字段

Spring 官網參考地址

http://docs.spring.io/spring-data/jpa/docs/1.11.0.M1/reference/html/