How to use the Eaxmple in SPRING-BOOT-STARTER-DATA-JPA

This article simply describes exact matches (' where * = * ') in SQL, string search (' where * * like%name% ' in SQL).

If you need more advanced applications, you can refer to the Spring JPA official sample portal.

I. Preparatory work

1. Create a standard spring boot JPA program and configure the database connection

Pom.xml

... < Dependency >    < groupId >org.springframework.boot</groupId>    <  Artifactid>spring-boot-starter-data-jpa</artifactid>  </dependency> ...

2. Entity class User.java

... @Entity  Public class User {    @Id    @GeneratedValue    private  Integer Id;     Private String name;     Private Short type;    @Override    public  String toString () {        return "user{" +                "id=" + ID +                ", name= '" + name + ' \ ' +                ", type=" + Type +                '} ';    } // ... Setter/getter..}

3.Repository Userrepository.java

... Import org.springframework.data.jpa.repository.JpaRepository;  Public Interface extends Jparepository<user, integer> {}

Two. Test program Userservice.java, run application to see results

@Component @transactional Public classUserService {Private Finaluserrepository userrepository; PrivateLogger Logger = Loggerfactory.getlogger ( This. GetClass ()); @Autowired PublicUserService (userrepository userrepository) { This. Userrepository =userrepository; //Initializing Datainit (); //Test Check NewPrintall ("Exact data lookup through Example", Querybyexample ()); Printall ("Match by Example string", Querybyexamplematcher ()); } Collection<User>querybyexample () {User User=NewUser (); User.settype (( Short) 1); Example<User> userexample =example.of (user); returnUserrepository.findall (userexample); } Collection<User>Querybyexamplematcher () {User User=NewUser (); User.setname ("10010"); Example<User> userexample = Example.of (User, Examplematcher.matching (). Withmatcher ("name",                /*StartsWith, 10010% * endsWith,%10010 * contains * */ExampleMatcher.GenericPropertyMatchers.startsWith ())); returnUserrepository.findall (userexample); }    voidPrintall (String Pre, collection<user>useriterator) {Logger.info ("Traverse user list {}", pre);  for(User u:useriterator) {logger.info (u.tostring ()); }    }    voidinit () { for(inti = 0; i < 443; i++) {Userrepository.save (NewUser (("+" + i + "00111" + i), ( Short) (I% 3))); }    }    }

How to use the Eaxmple in SPRING-BOOT-STARTER-DATA-JPA