資料庫的操作增刪改查，或者CRUD是最常見的操作。這篇文章中介紹修改資料的方法

hibernate.cfg.xml

建立如下所示的hibernate的設定檔案

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
  "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
  <session-factory
 
>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>

    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hbtestdb?useSSL=false</property
 
>
    <property name="hibernate.connection.username">hbtestuser01</property>
    <property name="hibernate.connection.password">hbtestuser01</property>

    <property name="show_sql">true</property>

    <property name="current_session_context_class">thread</property
 
>
  </session-factory>
</hibernate-configuration>

Entity Class：User

我們將會建立一個Entity的User類。Entity類就是用來與資料庫的Table進行Mapping的Class。

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Column;

@Entity
@Table (name="hbtableuser")
public class User {
  @Id
  @Column(name="userid")
  private int userid;

  @Column(name="username")
  private String username;

  @Column(name="country")
  private String country;

  public  User(){
    System.out.println("Default User construction is called...");
  }
  public User(int userid, String username, String country) {
    this.userid = userid;
    this.username = username;
    this.country = country;
  }

  public int getUserid() {
    return userid;
  }

  public void setUserid(int userid) {
    this.userid = userid;
  }

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getCountry() {
    return country;
  }

  public void setCountry(String country) {
    this.country = country;
  }
}

使用xml檔案自然也可以，由於註解可能是今後的標準方向，相關的例子都回使用註解方式。

事前確認

建立Demo演示程式碼

import org.hibernate.Session;
import org.hibernate.SessionFactory;

public class HbDemo04 {
  public static void main(String[] args){
    try{
      SessionFactory sessionFactory = new org.hibernate.cfg.Configuration()
        .configure("hibernate.cfg.xml")
        .addAnnotatedClass(User.class)
        .buildSessionFactory();

      Session session = sessionFactory.getCurrentSession();
      System.out.println("Successfully got connection from session factory.");
      session.beginTransaction();
      User user = session.get(User.class,1001);
      user.setUsername("liumiao");
      user.setCountry("PRC");
      session.getTransaction().commit();

      sessionFactory.close();
    }catch (Exception e){
      System.out.println("Exception happened...");
      e.printStackTrace();
    }
  }
}

執行結果

十二月 12, 2016 9:27:02 下午 org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.2.5.Final}
十二月 12, 2016 9:27:02 下午 org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
十二月 12, 2016 9:27:02 下午 org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
十二月 12, 2016 9:27:02 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
十二月 12, 2016 9:27:02 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/hbtestdb?useSSL=false]
十二月 12, 2016 9:27:02 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=hbtestuser01, password=****}
十二月 12, 2016 9:27:02 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
十二月 12, 2016 9:27:02 下午 org.hibernate.engine.jdbc.connections.internal.PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
十二月 12, 2016 9:27:03 下午 org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
Successfully got connection from session factory.
Hibernate: select user0_.userid as userid1_0_0_, user0_.country as country2_0_0_, user0_.username as username3_0_0_ from hbtableuser user0_ where user0_.userid=?
Default User construction is called...
Hibernate: update hbtableuser set country=?, username=? where userid=?
十二月 12, 2016 9:27:03 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:mysql://localhost:3306/hbtestdb?useSSL=false]

建立Demo演示程式碼

刪除和更新還可以使用另外一種方法來進行。程式碼如下

import org.hibernate.Session;
import org.hibernate.SessionFactory;

public class HbDemo04 {
  public static void main(String[] args){
    try{
      SessionFactory sessionFactory = new org.hibernate.cfg.Configuration()
        .configure("hibernate.cfg.xml")
        .addAnnotatedClass(User.class)
        .buildSessionFactory();

      Session session = sessionFactory.getCurrentSession();
      System.out.println("Successfully got connection from session factory.");
      session.beginTransaction();
      session.createQuery("update User set username='Michael' , country='China' where userid=1001 ").executeUpdate();
      session.getTransaction().commit();

      sessionFactory.close();
    }catch (Exception e){
      System.out.println("Exception happened...");
      e.printStackTrace();
    }
  }
}

注意update語句的Table名稱

執行結果

十二月 12, 2016 9:28:56 下午 org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.2.5.Final}
十二月 12, 2016 9:28:56 下午 org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
十二月 12, 2016 9:28:56 下午 org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
十二月 12, 2016 9:28:56 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
十二月 12, 2016 9:28:56 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/hbtestdb?useSSL=false]
十二月 12, 2016 9:28:56 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=hbtestuser01, password=****}
十二月 12, 2016 9:28:56 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
十二月 12, 2016 9:28:56 下午 org.hibernate.engine.jdbc.connections.internal.PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
十二月 12, 2016 9:28:57 下午 org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
Successfully got connection from session factory.
十二月 12, 2016 9:28:57 下午 org.hibernate.hql.internal.QueryTranslatorFactoryInitiator initiateService
INFO: HHH000397: Using ASTQueryTranslatorFactory
Hibernate: update hbtableuser set username='Michael', country='China' where userid=1001
十二月 12, 2016 9:28:57 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:mysql://localhost:3306/hbtestdb?useSSL=false]