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.bootgroupId>
            <artifactId>spring-boot-starter-data-jpaartifactId>
dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <scope>runtimescope>
        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 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 findList() {
        return userRepository.findAll();
    }

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

    public void saveListUser(List 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 list = new ArrayList();
        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