spring boot（二）spring data jpa以及事物配置

本章目的：使用spring data jpa连接mysql，实现增删改查和事物的配置。

• pom.xml引入jar

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>

• application.properties配置数据源

server.port=20001
spring.datasource.url=jdbc:mysql://localhost:3307/crawler
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.properties.hibernate.hbm2ddl.auto=update

• 创建实体类User

@Entity
public class User {
private Long id;
private String name;
private Integer age;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public Long getId() {
return id;
    }

public void setId(Long id) {
this.id = id;
    }

@Column(nullable = false)
public String getName() {
return name;
    }

public void setName(String name) {
this.name = name;
    }

@Column(nullable = false)
public Integer getAge() {
return age;
    }

public void setAge(Integer age) {
this.age = age;
    }

}

• 创建UserRepository

public interface UserRepository extends JpaRepository<User, Long> {
    User findByName(String name);

    User findByAgeGreaterThan(Integer age);

List<User> findByNameLike(String name);

}

• 创建UserService

@Service
public class UserService {
@Autowired
private UserRepository userRepository;

public User findUser(String name) {
return userRepository.findByName(name);
    }

public List<User> findList() {
return userRepository.findAll();
    }

public Long save(User user) {
return userRepository.save(user).getId();
    }

public void saveListUser(List<User> list) {
for (User user : list)
            save(user);
    }

}

• 创建API

@RestController
@RequestMapping("/user")
public class UserWeb {
@Autowired
private UserService userService;

@RequestMapping("/find")
public String findUser(String name) throws Exception {
return userService.findUser(name).getName();
    }

@RequestMapping("list")
public String list() throws JSONException {
        JSONObject out = new JSONObject();
        out.put("list", userService.findList());
return out.toString();
    }

@RequestMapping("/save")
public String save(String name, Integer age) {
        User user = new User();
        user.setName(name);
        user.setAge(age);
        Long id = userService.save(user);
return id.toString();
    }

@RequestMapping("/saveList")
public String saveList(String name, Integer age) {
        List<User> list = new ArrayList<User>();
for (int i = 6; i < 11; i++) {
            User user = new User();
            user.setName(name + "_0000" + i);
            user.setAge(age);
            list.add(user);
        }
        userService.saveListUser(list);
return "OK";
    }
}

启动主程序，访问http://localhost:20001/list获取user列表

• 事物
  springboot中的事物非常简单，只需要两步

• 主程序中加入注解@EnableTransactionManagement

• service方法中加入注解@Transactional