hibernate基础（注解）

package anno;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;

import java.lang.annotation.Documented;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({METHOD,TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface JDBCConfig {
     String ip(); 
     int port() default 3306; 
     String database(); 
     String encoding(); 
     String loginName(); 
     String password(); 
}

package util;

import anno.JDBCConfig;

@JDBCConfig(ip = "127.0.0.1", database = "test", encoding = "UTF-8", loginName = "root", password = "admin")
public class DBUtil {
	static {
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

}

package util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import anno.JDBCConfig;

@JDBCConfig(ip = "127.0.0.1", database = "test", encoding = "UTF-8", loginName = "root", password = "admin")
public class DBUtil {
	static {
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

	public static Connection getConnection() throws SQLException, NoSuchMethodException, SecurityException {
		JDBCConfig config = DBUtil.class.getAnnotation(JDBCConfig.class);

		String ip = config.ip();
		int port = config.port();
		String database = config.database();
		String encoding = config.encoding();
		String loginName = config.loginName();
		String password = config.password();

		String url = String.format("jdbc:mysql://%s:%d/%s?characterEncoding=%s", ip, port, database, encoding);
		return DriverManager.getConnection(url, loginName, password);
	}
	
	public static void main(String[] args) throws NoSuchMethodException, SecurityException, SQLException {
		Connection c = getConnection();
		System.out.println(c);
	}
}

package util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import anno.JDBCConfig;

public class DBUtilChild extends DBUtil {
	
	public static Connection getConnection2() throws SQLException, NoSuchMethodException, SecurityException {
		JDBCConfig config = DBUtilChild.class.getAnnotation(JDBCConfig.class);
		String ip = config.ip();
		int port = config.port();
		String database = config.database();
		String encoding = config.encoding();
		String loginName = config.loginName();
		String password = config.password();

		String url = String.format("jdbc:mysql://%s:%d/%s?characterEncoding=%s", ip, port, database, encoding);
		return DriverManager.getConnection(url, loginName, password);
	}
	
	public static void main(String[] args) throws NoSuchMethodException, SecurityException, SQLException {
		Connection c = getConnection2();
		System.out.println(c);
	}
}

@Entity
public class Employee{
    private Department dp;
}

@Embeddable
public class Department{
}

@Entity
@Table(name = "product_")
public class Product {
    int id;
    String name;
    float price;
     
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")  
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name = "name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @Column(name = "price")
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
      
}

public class Student{
    private String id;
    private IdCard idCard;
    ...
    @OneToOne(cascade=CascadeType.ALL) // 级联关系（数据同步，删除一边，另一边也删除等）
    @JoinColumn(name="cid",unique=true) // 外键名称
    public IdCard setIdCard(){
        	this.idCard = idCard;
    	}
    } 
}
public class IdCard{
    private String iid;
    ...
}

public class Student{
    private String id;
    private IdCard card;
    ...
    @OneToOne(cascade=CascadeType.ALL) // 级联关系（数据同步，删除一边，另一边也删除等）
    @JoinColumn(name="cid",unique=true) // 外键名称
    public IdCard setCard(){
        this.idCard = idCard;
    }
}

public class IdCard{
    private String iid;
    private Student student;
    @OneToOne(mappedBy("card")) //card是指Student.card
    public Student setStudent(){
    }
    ...
}

public class Student{
    private String id;
    private ClassRoom classRoom;
    ...
    @ManyToOne(cascade={CascadeType.ALL},fetch=FetchType.EAGER) //级联关系，抓取规则
    // @JoinColumn中的name为当前类的属性名，（多对一单向，有多方维护）所以，name为student中的cid，而ReferenceColumnName为引用表的列（多对一单向，所以为一方的引用列）即ClassRoom中的主键列
    @JoinColumn(name="cid",referencedColumnName="CID")  
    public CLassRoom setClassRoom(ClassRoom classRoom){
        this.classRoom = classRoom;
    } 
}

public class ClassRoom{
    private String cid;
    ...
}

public class Student{
    private String id;
    private ClassRoom classRoom;
    ...
    @ManyToOne(cascade={CascadeType.ALL},fetch=FetchType.EAGER) //级联关系，抓取规则
    // name为ClassRoom.cid
    @JoinColumn(name="cid") 
    public CLassRoom setClassRoom(ClassRoom classRoom){
        this.classRoom = classRoom;
    } 
}

// ClassRoom添加
public class ClassRoom{
    private String cid;
    private Map<String,Student> student;

    @OneToMany(cascade={CascadeType.ALL},fetch=FetchType.LAZY) //级联关系，抓取规则
    @JoinColumn(name="cid") 
    public Map<String,Student> getStudent(){
    }
    ...
}

//Teacher类
@ManyToMany
@JoinTable(name="student_teacher",//中间表名
joinColumns=@JoinColumn(name="teacher_id"),//这个类在表中的id
inverseJoinColumns=@JoinColumn(name="student_id")//反转的类在联合表中的id
)
public Set<Student> getStudentSet() {
return studentSet;
}

//Teacher类
@ManyToMany
@JoinTable(name="student_teacher",
joinColumns=@JoinColumn(name="teacher_id"),//这个类在表中的id
inverseJoinColumns=@JoinColumn(name="student_id")//反转的类在联合表中的id
)
public Set<Student> getStudentSet() {
	return studentSet;
}

//Student类
@ManyToMany(mappedBy="studentSet")
public Set<Teacher> getSet() {
	return set;
}