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1.pom添加依赖
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org.springframework.boot spring-boot-starter-data-jpa MySQL mysql-connector-java 5.1.42
2.添加数据源配置（DataSource啥的，一系列对象spring boot 都会给你注入的，配置配置即可！）
spring.datasource.url=jdbc:mysql://localhost/test?characterEncoding=utf8&useSSL=true spring.datasource.username=root spring.datasource.password=123456 spring.datasource.driver-class-name=com.mysql.jdbc.Driver #database pool config # Number of ms to wait before throwing an exception if no connection is available. spring.datasource.tomcat.max-wait=10000 # Maximum number of active connections that can be allocated from this pool at the same time. spring.datasource.tomcat.max-active=300 # Validate the connection before borrowing it from the pool. spring.datasource.tomcat.test-on-borrow=true # initial pool size spring.datasource.tomcat.initial-size=20 #=====================jpa config================================ #实体类维护数据库表结构的具体行为：update/create/create-drop/validate/none spring.jpa.hibernate.ddl-auto=none #打印sql语句 spring.jpa.show-sql=true #格式化输出的json字符串 spring.jackson.serialization.indent_output=true
3.新建实体
@Entity
@Table(name="user")
public class User {
@Id
@Column(name="id")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Column(name="number")
private String number;
@Column(name="name")
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}4.dao层
public interface UserDao{
User getById(int id);
User getByNumber(String number);
int addUser(User user);
void deleteUserById(int id);
User updateUser(User user);
}@Repository
public class UserDaoImpl implements UserDao {
@PersistenceContext
private EntityManager entityManager;
@Override
public User getById(int id) {
//find by primary key
return this.entityManager.find(User.class,id);
}
@Override
public User getByNumber(String number) {
Query query = this.entityManager.createQuery("from User u where u.number=:number",User.class);
query.setParameter("number",number);
User user = (User)query.getSingleResult();
return user;
}
@Override
public int addUser(User user) {
this.entityManager.persist(user);
//print the id
System.out.println(user.getId());
return user.getId();
}
@Override
public void deleteUserById(int id) {
User user = this.entityManager.find(User.class,id); //关联到记录，方可删除
this.entityManager.remove(user);
}
@Override
public User updateUser(User user) {
User userNew = this.entityManager.merge(user);
return userNew;
}
}5.service层
public interface UserService {
User getById(int id);
User getByNumber(String number);
int addUser(User user,boolean throwEx);
void deleteUserById(int id);
User updateUser(User user);
}@Service
@Transactional
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;
@Override
@Transactional(readOnly = true)
public User getById(int id) {
return userDao.getById(id);
}
@Override
@Transactional(readOnly = true)
public User getByNumber(String number) {
return userDao.getByNumber(number);
}
@Override
public int addUser(User user,boolean throwEx) {
int id= this.userDao.addUser(user);
if(throwEx){
throw new RuntimeException("throw a ex");
}
return id;
}
@Override
public void deleteUserById(int id) {
this.userDao.deleteUserById(id);
}
@Override
public User updateUser(User user) {
return this.userDao.updateUser(user);
}
}6.controller层
@Controller("user1")
@RequestMapping("/jpa/user")
public class UserController {
/**
* 日志（slf4j->logback）
*/
private static final Logger logger = LoggerFactory.getLogger(UserController.class);
@Autowired
private UserService userService;
/**
* 返回text格式数据
* @param id 主键id
* @return 用户json字符串
*/
@RequestMapping("/get/id/{id}")
@ResponseBody
public String getUserById(@PathVariable("id")String id){
logger.info("request /user/get/id/{id}, parameter is "+id);
User user = userService.getById(Integer.parseInt(id));
return JSONObject.toJSONString(user);
}
/**
* 返回json格式数据
* @param number 编号
* @return 用户
*/
@RequestMapping("/get/number/{number}")
@ResponseBody
public User getUserByNumber(@PathVariable("number")String number){
User user = userService.getByNumber(number);
return user;
}
@RequestMapping("/add/{number}/{name}")
@ResponseBody
public String addUser(@PathVariable("number")String number,@PathVariable("name")String name,boolean throwEx){
User user = new User();
user.setNumber(number);
user.setName(name);
int id = -1;
try{
id = userService.addUser(user,throwEx);
}catch (RuntimeException ex){
System.out.println(ex.getMessage());
}
return String.valueOf(id);
}
@RequestMapping("/delete/{id}")
@ResponseBody
public void getUserById(@PathVariable("id")int id){
this.userService.deleteUserById(id);
}
@RequestMapping("/update/{id}/{number}/{name}")
@ResponseBody
public User addUser(@PathVariable("id")int id, @PathVariable("number")String number, @PathVariable("name")String name){
User user = new User();
user.setId(id);
user.setNumber(number);
user.setName(name);
return userService.updateUser(user);
}
}7. spring data jpa新使用方式，更高级