SpringBoot连接MYSQL数据库并使用JPA进行操作

<!--数据库相关配置--> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-web</artifactId> 
    </dependency> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-data-jpa</artifactId> 
    </dependency> 
    <dependency> 
      <groupId>mysql</groupId> 
      <artifactId>mysql-connector-java</artifactId> 
    </dependency> 
    <dependency> 
      <groupId>org.apache.poi</groupId> 
      <artifactId>poi</artifactId> 
      <version>3.11</version> 
    </dependency> 

spring.datasource.url = jdbc:mysql://localhost:3306/webtest 
spring.datasource.username = root 
spring.datasource.password = 220316 
spring.datasource.driverClassName = com.mysql.jdbc.Driver 
# Specify the DBMS 
spring.jpa.database = MYSQL 
# Show or not log for each sql query 
spring.jpa.show-sql = true 
# Hibernate ddl auto (create, create-drop, update) 
spring.jpa.hibernate.ddl-auto = update 
# Naming strategy 
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy 
# stripped before adding them to the entity manager) 
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect 

package example.entity; 
import javax.persistence.*; 
import javax.validation.constraints.NotNull; 
import java.math.BigDecimal; 
import java.util.Date; 
@Entity 
@Table(name = "user") 
public class User { 
  @Id 
  @GeneratedValue(strategy = GenerationType.AUTO) 
  private int id; 
 
  @Column(name = "name", nullable = true, length = 30) 
  private String name; 
 
  @Column(name = "height", nullable = true, length = 10) 
  private int height; 
 
  @Column(name = "sex", nullable = true, length = 2) 
  private char sex; 
 
  @Temporal(TemporalType.DATE) 
  private Date birthday; 
 
  @Temporal(TemporalType.TIMESTAMP) 
  private Date sendtime; // 日期类型，格式：yyyy-MM-dd HH:mm:ss 
 
  @Column(name = "price", nullable = true, length = 10) 
  private BigDecimal price; 
 
  @Column(name = "floatprice", nullable = true, length = 10) 
  private float floatprice; 
 
 
  @Column(name = "doubleprice", nullable = true, length = 10) 
  private double doubleprice; 
 
  public Date getSendtime() { 
    return sendtime; 
  } 
 
  public void setSendtime(Date sendtime) { 
    this.sendtime = sendtime; 
  } 
 
  public BigDecimal getPrice() { 
    return price; 
  } 
 
  public void setPrice(BigDecimal price) { 
    this.price = price; 
  } 
 
  public float getFloatprice() { 
    return floatprice; 
  } 
 
  public void setFloatprice(float floatprice) { 
    this.floatprice = floatprice; 
  } 
 
  public double getDoubleprice() { 
    return doubleprice; 
  } 
 
  public void setDoubleprice(double doubleprice) { 
    this.doubleprice = doubleprice; 
  } 
 
  public User() { } 
 
  public char getSex() { 
    return sex; 
  } 
 
  public void setSex(char sex) { 
    this.sex = sex; 
  } 
 
  public Date getBirthday() { 
    return birthday; 
  } 
 
  public void setBirthday(Date birthday) { 
    this.birthday = birthday; 
  } 
 
  public User(int id) { 
    this.id = id; 
  } 
 
  public int getId() { 
    return id; 
  } 
 
  public void setId(int id) { 
    this.id = id; 
  } 
 
  public String getName() { 
    return name; 
  } 
 
  public void setName(String name) { 
    this.name = name; 
  } 
 
  public int getHeight() { 
    return height; 
  } 
 
  public void setHeight(int height) { 
    this.height = height; 
  } 
} 

package example.dao; 
import example.entity.User; 
import org.springframework.data.repository.CrudRepository; 
import javax.transaction.Transactional; 
import java.math.BigDecimal; 
import java.util.Date; 
import java.util.List; 
 
@Transactional 
public interface UserDao extends CrudRepository<User, Integer> { 
  public List<User> findByName(String name); 
  public List<User> findBySex(char sex); 
  public List<User> findByBirthday(Date birthday); 
  public List<User> findBySendtime(Date sendtime); 
  public List<User> findByPrice(BigDecimal price); 
  public List<User> findByFloatprice(float floatprice); 
  public List<User> findByDoubleprice(double doubleprice); 
} 

package example.controller; 
import example.dao.UserDao; 
import example.entity.User; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.ResponseBody; 
import java.math.BigDecimal; 
import java.text.ParseException; 
import java.text.SimpleDateFormat; 
import java.util.Date; 
import java.util.List; 
@Controller 
public class UserController { 
  @Autowired 
  private UserDao userDao; 
  @RequestMapping("/getName") 
  @ResponseBody 
  public String getByName(String name) { 
    List<User> userList = userDao.findByName(name); 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + name + " is not exist."; 
  } 
 
  @RequestMapping("/getSex") 
  @ResponseBody 
  public String getBySex(char sex) { 
    List<User> userList = userDao.findBySex(sex); 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + sex + " is not exist."; 
  } 
 
  @RequestMapping("/getBirthday") 
  @ResponseBody 
  public String findByBirthday(String birthday) { 
    System.out.println("birthday:"+birthday); 
    SimpleDateFormat formate=new SimpleDateFormat("yyyy-MM-dd"); 
    List<User> userList = null; 
    try { 
      userList = userDao.findByBirthday(formate.parse(birthday)); 
    } catch (ParseException e) { 
      e.printStackTrace(); 
    } 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + birthday + " is not exist."; 
  } 
 
  @RequestMapping("/getSendtime") 
  @ResponseBody 
  public String findBySendtime(String sendtime) { 
    System.out.println("sendtime:"+sendtime); 
    SimpleDateFormat formate=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
    List<User> userList = null; 
    try { 
      userList = userDao.findBySendtime(formate.parse(sendtime)); 
    } catch (ParseException e) { 
      e.printStackTrace(); 
    } 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + sendtime + " is not exist."; 
  } 
 
  @RequestMapping("/getPrice") 
  @ResponseBody 
  public String findByPrice(BigDecimal price) { 
    List<User> userList = null; 
    userList = userDao.findByPrice(price); 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + price + " is not exist."; 
  } 
 
  @RequestMapping("/getFloatprice") 
  @ResponseBody 
  public String findFloatprice(float floatprice) { 
    List<User> userList = null; 
    userList = userDao.findByFloatprice(floatprice); 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + floatprice + " is not exist."; 
  } 
 
  @RequestMapping("/getDoubleprice") 
  @ResponseBody 
  public String findByPrice(double doubleprice) { 
    List<User> userList = null; 
    userList = userDao.findByDoubleprice(doubleprice); 
    if (userList != null && userList.size()!=0) { 
      return "The user length is: " + userList.size(); 
    } 
    return "user " + doubleprice + " is not exist."; 
  } 
}