Hibernate的使用以及注意事项-蒲公英云

Hibernate的使用以及注意事项

忘是亡心i 2021-09-28 20:24 528阅读 0赞

目录结构：

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1、导包，所需的jar包有：

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相关jar包可以到https://mvnrepository.com/这里进行搜索并下载

2、新建javabean对象，即实体类User.java

package com.hibernate.pojo;
public class User {
    private int id;
    private String name;
    private int age;
    private String description;
    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 getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", description='" + description + '\'' +
                '}';
    }
}

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3、新建并编写对象映射（User.hbm.xml）；就在User.java的同级目录下新建

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--在pojo包下-->
<hibernate-mapping package="com.hibernate.pojo">
    <!--类名为User，表名为person-->
    <class name="User"  table="person">
        <!--主键映射，属性名为id，列名也为id-->
        <id name="id" column="id">
            <!--根据底层数据库主键自动增长-->
            <generator class="native"/>
        </id>
        <!--非主键映射，属性和列名一一对应-->
        <property name="name" column="name"/>
        <property name="age" column="age"/>
        <property name="description" column="description"/>
    </class>
</hibernate-mapping>

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注意：实体类名对应表名，属性名对应数据库字段名。**User.hbm.xml文件开头的文档类型声明和下面hibernate.cfg.xml**中的不一样

4、src文件下创建并编写Hirbernate的主配置文件（hibernate.cfg.xml）

<?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>
    <!-- 通常，一个session-factory节点代表一个数据库 -->
    <session-factory>
        <!--驱动路径注意数据库类型  -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <!--数据库路径  -->
        <property name="connection.url">jdbc:mysql://127.0.0.1:3306/userinfo?useUnicode=true&characterEncoding=utf-8&&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=GMT%2B8</property>
        <!--数据库用户名  -->
        <property name="connection.username">root</property>
        <!--数据库密码  -->
        <property name="connection.password">123456</property>
        <!--方言，便于hibernate对象操作转化为合适的数据库语句  -->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
        <!--是否显示sql语句，sql一般会很难看  默认为false-->
        <property name="hibernate.show_sql">true</property>
        <!-- 2.3 自动建表  -->
<!--        <property name="hibernate.hbm2ddl.auto">create</property>-->
        <!--下一个层级的映射文件，用来配置bean对象与数据表之间的关系  -->
        <mapping resource="com/hibernate/pojo/User.hbm.xml"/>
    </session-factory>
</hibernate-configuration>