第三节 基于Annotation注解实现数据的CURD

基于Annotation注解实现数据的CURD

hibernate注解主要解决实体类和*.hbm.xml的配置问题

hibernate使用注解后，hibernate.cfg.xml不再需要大量的mapping

<mapping class="cn.edu.scnu.annotationcurd.entity.User/>

<mapping package="cn.edu.scnu.annotationcurd.entity"/>

实体类注解实现

package cn.edu.scnu.annotationcurd.entity;

import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;

/**
 * 1. 使用@Entity注解表示实体类
 * 2. 使用@Table注解表示数据库 name-数据表名   catalog-数据库名
 * 3. 使用@Id注解表示主键
 * 4.  @GeneratedValue(generator = "native")
 *     @GenericGenerator(name = "native",strategy = "native")
 *     指定主键生成策略
 * 5. 使用@Column表示列,unique-唯一   nullable-是否可为空
 */
@Entity
@Table(name = "users",catalog = "hibernate")
public class User {

    @Id
    @GeneratedValue(generator = "native")
    @GenericGenerator(name = "native",strategy = "native")
    @Column(name = "id",unique = true,nullable = false)
    private Integer id;
    @Column(name = "username",length = 16,nullable = false)
    private String username;
    @Column(name = "password",length = 16,nullable = false)
    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}