Spring boot中使用Spring-data-jpa方便快捷的访问数据库(推荐)

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

<dependency>
 <groupId>com.h2database</groupId>
 <artifactId>h2</artifactId>
 <scope>runtime</scope>
</dependency>

<dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <version>5.1.38</version>
</dependency>

spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

@Service
public class DemoSerivce {
 @Autowired
 private JdbcTemplate jdbcTemplate;
 public void create(String name, Integer age) {
  jdbcTemplate.update("insert into DEMO(NAME, AGE) values(?, ?)", name, age);
 }
 public void deleteByName(String name) {
  jdbcTemplate.update("delete from DEMOwhere NAME = ?", name);
 }
 public Integer getAllDemo() {
  return jdbcTemplate.queryForObject("select count(1) from DEMO", Integer.class);
 }
 public void deleteAllDemo() {
  jdbcTemplate.update("delete from DEMO");
 }
}

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
</dependency>

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(Main.class)
public class ApplicationTests {
 @Autowired
 private DemoSerivce demoSerivce;
 @Before
 public void setUp() {
 // 准备，清空表
 demoSerivce.deleteAllDemo();
 }
 @Test
 public void test() throws Exception {
 // 插入5个
 demoSerivce.create("a", 1);
 demoSerivce.create("b", 2);
 demoSerivce.create("c", 3);
 demoSerivce.create("d", 4);
 demoSerivce.create("e", 5);
 Assert.assertEquals(5, demoSerivce.getAllDemo().intValue());
 demoSerivce.deleteByName("a");
 demoSerivce.deleteByName("e");
 // 查数据库，应该有5个
 Assert.assertEquals(3, demoSerivce.getAllDemo().intValue());
 }
}

<dependency
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.properties.hibernate.hbm2ddl.auto=update

@Entity
public class DemoEntity {
 @Id
 @GeneratedValue
 private long id;
 private String title;
 private String content;
 public DemoEntity() {
 }
 public DemoEntity(String title, String content) {
 this.title = title;
 this.content = content;
 }
 // get set 略
}

public interface DemoRepository extends JpaRepository<DemoEntity, Long> {
 DemoEntity findByTitle(String title);
 DemoEntity findByTitleAndContent(String title, String content);
// @Query("select u from DemoEntity u where u.content=:content")
 @Query("from DemoEntity u where u.content=:content")
 DemoEntity sqlFind(@Param("content") String content);
}

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(Main.class)
public class UnitTest {
 @Autowired
 DemoRepository demoRepository;
 @Test
 public void test()
 {
 for(int i=0;i<10;i++)
 {
 demoRepository.save(new DemoEntity("title"+i, "content"+i));
 }
 Assert.assertEquals(10, demoRepository.findAll().size());
 }
 @Test
 public void testfindbytitle()
 {
 DemoEntity res = demoRepository.findByTitle("title8");
 Assert.assertEquals("title8", res.getTitle());
 }
 @Test
 public void testfindbytitleandcontent()
 {
 DemoEntity res = demoRepository.findByTitleAndContent("title9", "content9");
 Assert.assertEquals("title9", res.getTitle());
 Assert.assertEquals("content9", res.getContent());
 }
 @Test
 public void testsqlFind()
 {
 DemoEntity res = demoRepository.sqlFind("content7");
 Assert.assertEquals("content7", res.getContent());
 }
}