我目前正在学习Sping Boot ,并尝试使用MySQL数据库设置JPA。一切看起来都很好,项目正确启动,没有可见的错误,但是. ProjectApplication.java
package com.first.project;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class ProjectApplication {
public static void main(String[] args) {
SpringApplication.run(ProjectApplication.class, args);
}
}
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我的学生班级:
package com.first.project.student;
import org.springframework.data.annotation.Id;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Table;
import java.time.LocalDate;
@Entity
@Table
public class Student {
@Id
@GeneratedValue(
strategy = GenerationType.IDENTITY
)
private Long id;
private String name;
private String email;
private LocalDate dateOfBirth;
private Integer age;
public Student() {
}
public Student(Long studentId, String studentName, String studentEmail, LocalDate studentDoB, Integer studentAge) {
this.id = studentId;
this.name = studentName;
this.email = studentEmail;
this.dateOfBirth = studentDoB;
this.age = studentAge;
}
public Student(String studentName, String studentEmail, LocalDate studentDoB, Integer studentAge) {
this.name = studentName;
this.email = studentEmail;
this.dateOfBirth = studentDoB;
this.age = studentAge;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public LocalDate getDateOfBirth() {
return dateOfBirth;
}
public void setDateOfBirth(LocalDate dateOfBirth) {
this.dateOfBirth = dateOfBirth;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", email='" + email + '\'' +
", dateOfBirth=" + dateOfBirth +
", age=" + age +
'}';
}
}
型
application.properties:
spring.datasource.url=jdbc:mysql://localhost:3306/(my database)
spring.datasource.username=(my username)
spring.datasource.password=(my password)
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQLDialect
spring.jpa.properties.hibernate.format_sql=true
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.properties.hibernate.show_sql=true
spring.jpa.generate-ddl=true
型
我的pom.xml文件中的依赖项:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>javax.persistence-api</artifactId>
<version>2.2</version>
</dependency>
</dependencies>
型
在主包中我有ProjectApplication,还有一个子包,里面有Student类。
有什么想法吗?
4条答案
按热度按时间f45qwnt81#
在application.properties文件中
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在这里,spring.jpa.hibernate.ddl-auto= update-drop表示应用程序在启动时创建表,并在退出时删除表。要在应用程序结束后查看表,您可以将其更改为spring.jpa.hibernate.ddl-auto=update。修改后的配置如下所示:
型
通过此更改,应用程序将在退出后保留这些表,以便您以后可以查看它们。
i2byvkas2#
你使用的是drop-drop,所以当你启动应用程序时会创建表,当你停止时会删除表,如果你的应用程序正在运行,仍然没有显示表,那么试着这样做:检查数据库名称是否与spring数据库匹配,并试着在mysqlworkbench中刷新
wqnecbli3#
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在pom文件中尝试这个
biswetbf4#
看起来你的sql没有连接,确保你添加了mysql连接器jar文件,或者可以简单地在你的pom.xml文件中添加这个命令
第一个月
有时候是因为你没有相应的端口,在mysql客户端命令行中通过以下代码检查你的端口:mysql -h your_host -P your_port -u your_username -p -e“SELECT @@port;”
希望这对你有帮助!