Question

我正在尝试在Spring启动项目中为H2数据库创建表。

模型类：

package model;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;

@Entity
public class Author {
    /* (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long id;
    /**
     * @return the id
     */
    public long getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public void setId(long id) {
        this.id = id;
    }

    @Override
    public String toString() {
        return "Author [firstName=" + firstName + ", lastName=" + lastName + ", books=" + books + "]";
    }

    private String firstName;
    /**
     * @return the firstName
     */
    public String getFirstName() {
        return firstName;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (int) (id ^ (id >>> 32));
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Author other = (Author) obj;
        if (id != other.id)
            return false;
        return true;
    }

    /**
     * @param firstName the firstName to set
     */
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    private String lastName;
    /**
     * @return the lastName
     */
    public String getLastName() {
        return lastName;
    }

    /**
     * @param lastName the lastName to set
     */
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    @ManyToMany(mappedBy="author")
    private Set<Book>books=new HashSet<>();
    /**
     * @return the books
     */
    public Set<Book> getBooks() {
        return books;
    }

    /**
     * @param books the books to set
     */
    public void setBooks(Set<Book> books) {
        this.books = books;
    }




    public Author() {}

    public Author(String firstName, String lastName) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public Author(String firstName, String lastName, Set<Book> books) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
        this.books = books;
    }

}

POM.xml ：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>10</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</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.data</groupId>
            <artifactId>spring-data-commons-core</artifactId>
            <version>1.4.1.RELEASE</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

应用程序属性：

spring.h2.console.enabled=true


spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.username=sa
spring.datasource.password=
spring.datasource.driver-class-name=org.h2.Driver
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

到H2数据库的连接日志：

er        : Located MBean 'dataSource': registering with JMX server as MBean [com.zaxxer.
hikari:name=dataSource,type=HikariDataSource]
2018-07-26 08:20:35.146  INFO 10708 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatW
ebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-07-26 08:20:35.146  INFO 10708 --- [  restartedMain] com.example.demo.DemoApplicatio
n         : Started DemoApplication in 8.807 seconds (JVM running for 9.771)

h2数据库中没有表，我整天都在搜索该问题，但是所有结果都返回到配置应用程序属性并将h2控制台更改为jdbc:h2:mem:testdb上。我已经尝试了所有这些，但没有任何变化。

Answer 1

您必须在属性文件中添加

spring.jpa.hibernate.ddl-auto=create

通过这种方式休眠将创建表

Answer 2

您是否正在扫描实体包裹？（即package model）？

如果您不扫描实体包，则在主类的下面添加一行。

@ComponentScan(basePackages= {"model"});

希望这可以解决您的问题

H2无法创建表

2 个答案: