JPA實(shí)體bean配置,jpa增刪改api,jpasql增刪改

1、.JPA實(shí)體 bean 配置， jpa 增刪改 api， jpasql 增刪改1.ORM 框架必然發(fā)展趨勢(shì)：jdbc-hibernate( 是產(chǎn)品，實(shí)現(xiàn)jpa 規(guī) )-jpa(是規(guī)，不是產(chǎn)品)。ps:運(yùn)用 jpa 規(guī)的 API 進(jìn)行編程，不對(duì)Hiberbate ， topLink 等 orm 框架構(gòu)成威脅。2.JPA環(huán)境搭建 hibernate-distribution-3.6.10.Final1.準(zhǔn)備 lib 包2.jar 包引入時(shí)，千萬注意目錄不能有中文或者空格3.開發(fā)步驟：1.先建表，再編寫配置文件和bean-（面向過程，傳統(tǒng)的數(shù)據(jù)庫建模思想）2.先編寫配置文件和bean，在建表 (OO

2、P 思想 )-要求比較高4.demo 實(shí)例事務(wù)種類：1.本地事務(wù)：支持對(duì)同一個(gè)數(shù)據(jù)庫的事務(wù)操作大部分應(yīng)用2.全局事務(wù)：支持對(duì)多個(gè)數(shù)據(jù)庫的事務(wù)操作(銀行轉(zhuǎn)賬 )-兩次提交協(xié)議步驟：第一步：項(xiàng)目結(jié)構(gòu)2.持久化文件配置：html view plain copy print? .3.實(shí)體 bean知識(shí)點(diǎn)： 字段的長(zhǎng)度， 是否為空， 關(guān)鍵字， 自增，字段名稱的映射修改，表名稱的映射修改 , 字段類型 (Date 類型 )-不同格式要求 ,枚舉類的注釋 (索引，枚舉值 )-性別 ,大文本類型數(shù)據(jù)，二進(jìn)制數(shù)據(jù)映射， 不想某個(gè)字段跟表有映射關(guān)系，為了防止某個(gè)字段數(shù)據(jù)量過大而占用存過大因此對(duì)其進(jìn)行延遲加載(懶惰

3、加載，需要獲取數(shù)據(jù)時(shí)才得到數(shù)據(jù))。java view plain copy print?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.Generated

4、Value;import javax.persistence.Id;import javax.persistence.Lob;import javax.persistence.Table;import javax.persistence.Temporal;import javax.persistence.TemporalType;import javax.persistence.Transient;EntityTable(name=person)public class Person private Integer id;private String name;private Date bir

5、thday;private Sex sex;private String info;private Byte file;private String other;public Person() super();public Person(String name) super(); = name;public Person(String name, Date birthday) super(); = name;.this.birthday = birthday;public Person(String name, Date birthday, Sex sex)

6、 super(); = name;this.birthday = birthday;this.sex = sex;/* 主鍵并自增* return the id*/Id GeneratedValuepublic Integer getId() return id;/* param id the id to set*/public void setId(Integer id) this.id = id;/* return the name*/Column(length=10,nullable=false,name=personName)public String getName

7、() return name;/* param name the name to set*/public void setName(String name) = name;/* return the birthday*/Temporal(TemporalType.DATE)public Date getBirthday() return birthday;/*.* param birthday the birthday to set*/public void setBirthday(Date birthday) this.birthday = birthday;/* ret

8、urn the sex*/Enumerated(EnumType.STRING)public Sex getSex() return sex;/* param sex the sex to set*/public void setSex(Sex sex) this.sex = sex;/* return the info*/Lobpublic String getInfo() return info;/* param info the info to set*/public void setInfo(String info) = info;/* return the fil

9、e*/Lob Basic(fetch=FetchType.LAZY) /當(dāng)文件很大時(shí)，進(jìn)行懶惰加載 public Byte getFile() return file;/* param file the file to set*/public void setFile(Byte file) this.file = file;./* return the other*/Transient / 排除某個(gè)字段的映射public String getOther() return other;/* param other the other to set*/public void setOther(St

10、ring other) this.other = other;枚舉類：java view plain copy print?public enum Sex MAN,WORMAN4.單元測(cè)試類知識(shí)點(diǎn)：1.把握異常出現(xiàn)的時(shí)機(jī)。2.通過 ID 得到實(shí)體bean(1.徹底查詢2.用到查詢 )3.保存實(shí)體bean 到數(shù)據(jù)庫4.更新實(shí)體bean 到數(shù)據(jù)庫中涉及到對(duì)象的狀態(tài)：1.新建2.托管 (設(shè)置實(shí)體的字段值，并通過提交可以同步到數(shù)據(jù)庫)3.游離 (無法更新到數(shù)據(jù)庫中，除非使用merge 方法重新可將其更新到數(shù)據(jù)庫中)4.刪除java view plain copy print?public class

11、PersonTest Testpublic void save()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa); EntityManager em=factory.createEntityManager(); em.getTransaction().begin();em.persist(new Person(techbirds,new Date(),Sex.MAN);em.getTransaction().commit();em.close();factory.close();.Testpu

12、blic void getPerson1()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa);EntityManager em=factory.createEntityManager();em.getTransaction().begin();Person p=em.find(Person.class, 1);em.getTransaction().commit();em.close();factory.close();System.out.println(p.getName();Testpub

13、lic void getPerson2()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa); EntityManager em=factory.createEntityManager(); em.getTransaction().begin();Person p=em.getReference(Person.class, 1);/ 代理對(duì)象，用到才查詢System.out.println(p.getName();em.getTransaction().commit();em.close();/S

14、ystem.out.println(p.getName();出錯(cuò)，事務(wù)已經(jīng)關(guān)閉factory.close();Testpublic void updatePerson1()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa); EntityManager em=factory.createEntityManager(); em.getTransaction().begin();Person p=em.find(Person.class, 1);p.setName(bao);em.getTransac

15、tion().commit();em.close();factory.close();Testpublic void updatePerson2()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa);EntityManager em=factory.createEntityManager();em.getTransaction().begin();Person p=em.find(Person.class, 1);em.clear();/ 將所有實(shí)體管理器中的所有實(shí)體變成游離狀態(tài)，無法跟數(shù)據(jù)庫同步

16、.p.setName(techbirds);em.getTransaction().commit();em.close();factory.close();public void updatePerson3()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa); EntityManager em=factory.createEntityManager();em.getTran .wang027. saction().begin();Person p=em.find(Person.class, 1)

17、;em.clear();/ 將所有實(shí)體管理器中的所有實(shí)體變成游離狀態(tài)，無法跟數(shù)據(jù)庫同步p.setName(techbirds);em.merge(p);/ 此時(shí)又可以進(jìn)行同步em.getTransaction().commit();em.close();factory.close();Testpublic void delPerson()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa); EntityManager em=factory.createEntityManager(); em.get

18、Transaction().begin();Person p=em.find(Person.class, 1);em.remove(p);em.getTransaction().commit();em.close();factory.close();5.jpa 的 (sql)查詢jpaSQL語句：面向?qū)ο蟮膕ql 語句， jpa 標(biāo)準(zhǔn)的 sql 語法查詢方法：1.位參數(shù)查詢select o from Person o where o.id=?1 query.setParameter(1,2);2.命名查詢select o from Person o where o.id=:id query.s

19、etParameter(id,2);查詢結(jié)果： 1.列表2.唯一值 (對(duì)象 )查詢類型：普通查詢，刪除查詢，更新查詢ps：進(jìn)行數(shù)據(jù)的更改必須啟動(dòng)事務(wù)。-刪除查詢和更新查詢必須開啟事務(wù)java view plain copy print?Testpublic void querysql()EntityManagerFactory factory=Persistence.createEntityManagerFactory(MyJpa); EntityManager em=factory.createEntityManager();./ 面向?qū)ο蟮?sql 語句Query query=em.createQuery(select o from Person o where o.id=?); query.setParameter(1, 2);Person p=(Person) query.getSingleResult();System.out.println(p.getName();em.close();factory.close();Testpublic void deletesql()EntityManagerFactory factory=Persistence.createEntityManagerFactory(M