Hibernate基础：快速入门(7)：查询数据

hibernate.cfg.xml

<?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

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;
}
}

创建Demo演示代码

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

public class HbDemo05 {
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 result = session.get(User.class,1001);
session.getTransaction().commit();
System.out.println("Username :" + result.getUsername());
System.out.println("Country: " + result.getCountry());
sessionFactory.close();
}catch (Exception e){
System.out.println("Exception happened...");
e.printStackTrace();
}
}
}

执行结果

十二月 12, 2016 9:32:54 下午 org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.2.5.Final}
十二月 12, 2016 9:32:54 下午 org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
十二月 12, 2016 9:32:55 下午 org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
十二月 12, 2016 9:32:55 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 9:32:55 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 9:32:55 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=hbtestuser01, password=****}
十二月 12, 2016 9:32:55 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
十二月 12, 2016 9:32:55 下午 org.hibernate.engine.jdbc.connections.internal.PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
十二月 12, 2016 9:32:55 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...
十二月 12, 2016 9:32:56 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:mysql://localhost:3306/hbtestdb?useSSL=false]
Username :Michael
Country: China