For example, its auto-configuration ability raises and configures JPA and Hibernate-related stuff:
DataSource, Entity and Transaction Managers, Repositories.
With no manual configuration in your code or in xml files.
And the application code is getting smaller and smaller...
User.java
package sb; import javax.persistence.*; @Entity @Table(name = "sb_user") public class User { @Id @GeneratedValue(strategy = GenerationType.AUTO) public long id; public String name; public String alias; public User() { } public User(long id, String name) { this.id = id; this.name = name; } }
UserRepository.java
package sb; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.data.jpa.repository.Query; import java.util.List; public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT u FROM User u WHERE u.alias IS NOT NULL") List<User> findAliased(); }
UserController.java
package sb; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import java.util.List; @RestController @RequestMapping("user") public class UserController { protected final Logger log = LoggerFactory.getLogger(getClass()); @Autowired private UserRepository users; @RequestMapping("test") public String test() { log.info("Test"); return "OK"; } @RequestMapping("user") public User getUser(@RequestParam("id") long id) { log.info("Get user"); return users.findOne(id); } @RequestMapping("users") public List<User> getUsers(@RequestParam("ids") List<Long> ids) { log.info("Get users"); return users.findAll(ids); } @RequestMapping("aliased") public List<User> getAliasedUsers() { log.info("Get aliased users"); return users.findAliased(); } }
Application.java
package sb; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; @EnableAutoConfiguration @Configuration @ComponentScan public class Application { public static void main(String[] args) throws Throwable { new SpringApplication(Application.class).run(args); } }
application.properties
spring.datasource.driverClassName=org.postgresql.Driver spring.datasource.url=jdbc:postgresql://srv0/test spring.datasource.username=test spring.datasource.password=test
schema.sql
-- DROP TABLE sb_user; CREATE TABLE sb_user ( id SERIAL PRIMARY KEY NOT NULL, name CHARACTER VARYING(65) NOT NULL, alias CHARACTER VARYING(20) ); INSERT INTO sb_user (name) VALUES ('Ben Linus'); INSERT INTO sb_user (name) VALUES ('Claire Littleton'); INSERT INTO sb_user (name) VALUES ('Desmond Hume'); INSERT INTO sb_user (name) VALUES ('Frank Lapidus'); INSERT INTO sb_user (name, alias) VALUES ('Hugo Reyes', 'Hurley'); INSERT INTO sb_user (name) VALUES ('Jack Shephard'); INSERT INTO sb_user (name, alias) VALUES ('James Ford', 'Sawyer'); INSERT INTO sb_user (name) VALUES ('Jin-Soo Kwon'); INSERT INTO sb_user (name) VALUES ('Miles Straume'); INSERT INTO sb_user (name) VALUES ('Richard Alpert'); INSERT INTO sb_user (name) VALUES ('Sayid Jarrah'); INSERT INTO sb_user (name) VALUES ('Sun-Hwa Kwon');
Build and run command:
gradle clean build runJar
Test urls:
http://localhost:8080/user/user?id=2 http://localhost:8080/user/users?ids=1,3,5,7 http://localhost:8080/user/aliased
5 comments:
Hello, I use your sample, but I get exception as bellow.
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [dao.UserRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1103)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:963)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:858)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
... 16 more
hello,
I got exception as bellow:
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [dao.UserRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
Help!! :)
Foarte tare. Mersi mult pentru postarea asta!
Thank you! I was looking for.
How to do the same with 2 different databases ?????
what changes need to be done in above code?????
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