JPA之大数据字段映射与字段延迟加载

来源：互联网发布：医疗大数据国内外现状编辑：程序博客网时间：2024/06/08 10:32

1、修改Person.java中的代码

package cn.sunft.bean;import java.util.Date;import javax.persistence.Basic;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.EnumType;import javax.persistence.Enumerated;import javax.persistence.FetchType;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.Lob;import javax.persistence.Table;import javax.persistence.Temporal;import javax.persistence.TemporalType;import javax.persistence.Transient;@Entity@Table(name="person")public class Person {private Integer id;private String name;private Date birthday = new Date();//1987-12-10private Gender gender = Gender.MAN;//设置默认属性private String info;               //大段文本信息private Byte[] file;               //大段二进制数据private String imagepth;           //希望该属性不成为持久化字段@Transient//该字段不与数据库进行映射public String getImagepth() {return imagepth;}public void setImagepth(String imagepth) {this.imagepth = imagepth;}@Lob//针对二进制文本的配置@Basic(fetch=FetchType.LAZY) //指定延迟加载public Byte[] getFile() {return file;}public void setFile(Byte[] file) {this.file = file;}@Lob//针对大段文本的注解public String getInfo() {return info;}public void setInfo(String info) {this.info = info;}//@Enumerated(EnumType.ORDINAL)//保存索引到数据库中@Enumerated(EnumType.STRING)//保存字面值到数据库@Column(length=5, nullable=false)//一定要加上非空约束public Gender getGender() {return gender;}public void setGender(Gender gender) {this.gender = gender;}@Temporal(TemporalType.DATE)public Date getBirthday() {return birthday;}public void setBirthday(Date birthday) {this.birthday = birthday;}public Person() {super();}public Person(String name) {super();this.name = name;}//也可以直接标注在属性上@Id@GeneratedValue(strategy=GenerationType.AUTO)public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}//指定列的长度@Column(length=10, nullable=false,name="personName")public String getName() {return name;}public void setName(String name) {this.name = name;}}

2、运行PersonTest.java中的save()方法(参见JPA第二篇博客)之后生成的数据库表结构

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