idea2018.3.2创建Hibernate入门项目

不念不忘少年蓝@ 2024-04-17 05:34 59阅读 0赞

### 具体步骤： ###

展示一下我的项目列表（其中常用jar包主要是为了导入连接数据库的dbutils，我为了方便一起导入）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70][]

1、新建Project（此处以创建web项目为例）   
勾选Web Application + Hibernate   
同时勾选 ”Create default hibernate configuration and main class” （当然也可以不勾选，在项目创建好后再手动创建也是一样的）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 1][]

2.点击configure选择如下所示，并完成创建：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 2][]

3.配置数据库（我的是mysql，在连接数据库之前，需创建好数据库）   
找到Database，点击如图所示 ，点击“Test Connection”测试连接成功，点击“Apply”，点击OK 连接成功

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 3][]

4.配置hibernate.cfg.xml（具体功能有注释）：

<?xml version='1.0' encoding='utf-8'?>
    <!DOCTYPE hibernate-configuration PUBLIC
            "-//Hibernate/Hibernate Configuration DTD//EN"
            "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
    <hibernate-configuration>
        <session-factory>
            
            <property name="connection.url">jdbc:mysql:///test_hibernate</property>
            <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
            <property name="connection.username">root</property>
            <property name="connection.password">123</property>
    
            
            
            <property name="hibernate.show_sql">true</property>
            
            <property name="hibernate.format_sql">true</property>
            
            <property name="hbm2ddl.auto">update</property>
            
            <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
    
            
            <mapping class="customer.Customer"/>
        </session-factory>
    </hibernate-configuration>

5.hibernate支持直接使用注解的形式，在实体类进行添加相应的注解，可以不用创建映射文件，我这里使用注解，但是也展示映射文件（需要注意的是如果使用注解需要改动一些东西）

1.hibernate核心配置文件变化
    <mapping resource="customer/customer.hbm.xml"/>
    改成
    <mapping class="customer.Customer"/>

customer.hbm.xml文件：

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE hibernate-mapping PUBLIC
            "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
            "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <hibernate-mapping>
        
        <class name="customer.Customer" table="customer">
            
            
            <id name="id" column="id">
                
                <generator class="native"></generator>
            </id>
            <property name="username" column="username"/>
            <property name="password" column="password"></property>
            <property name="address" column="address"></property>
        </class>
    </hibernate-mapping>

Customer实体类配置：

@Entity
    @Table(name = "customer")
    public class Customer {
        @Id  // 表示主键
        @GenericGenerator(name = "generator", strategy = "increment")
        @GeneratedValue(generator = "generator") // 自增长
        @Column(name = "id")  // 类属性对应着表字段
        private int id;
        private String username;
        private String password;
        private String address;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getUsername() {
            return username;
        }
    
        public void setUsername(String username) {
            this.username = username;
        }
    
        public String getPassword() {
            return password;
        }
    
        public void setPassword(String password) {
            this.password = password;
        }
    
        public String getAddress() {
            return address;
        }
    
        public void setAddress(String address) {
            this.address = address;
        }
    }

测试类：

public class test {
        public static void main(String[] args) {
            Configuration cfg = new Configuration();
            cfg.configure("hibernate.cfg.xml");
            SessionFactory sessionFactory = cfg.buildSessionFactory();
            Session session = sessionFactory.openSession();
            Transaction tx = session.beginTransaction();
            Customer customer = new Customer();
            customer.setUsername("AT&T");
            customer.setPassword("123456");
            customer.setAddress("美国");
            session.save(customer);
            tx.commit();
            session.close();
        }
    
    }

测试结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 4][]

数据库自动创建的表：

![20190822194435535.png][]

这里结束之后自己依然是有一个疑问，希望大家会的给出解答：

hibernate自动生成表格内容的类型尺寸显然不合理，可能是有什么属性没有设置还是其他问题？

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/3d7ebc2ee2624a7682e8b1dfc3766046.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 2]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/d9bd633ec2644cdcb46666509bcbd335.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 3]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/91d6ef6dda6d47e1ad25cd3aab9a7ac4.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NobGVpXw_size_16_color_FFFFFF_t_70 4]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/4da0980691d94ea38fe2dd9a8143fe22.png
[20190822194435535.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/40a00899aa0a473f98a8b359785dfbf3.png