@注解_双向一对多映射

直接上代码咯

package cn.jbit.test2.bean;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

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

@Entity
@Table(name = "test_district2")
public class District implements Serializable {

	private static final long serialVersionUID = -6358000709323619820L;

	@Id
	@GeneratedValue
	private Integer id;
	
	@Column(name = "name")
	private String name;
	
	@OneToMany(mappedBy = "district", targetEntity = Street.class)
	private Set<Street> streets = new HashSet<Street>();
	
	public District() {
		super();
	}

	public District(Integer id, String name, Set<Street> streets) {
		super();
		this.id = id;
		this.name = name;
		this.streets = streets;
	}

	public Integer getId() {
		return id;
	}

	@SuppressWarnings("unused")
	private void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	protected Set<Street> getStreets() {
		return streets;
	}

	protected void setStreets(Set<Street> streets) {
		this.streets = streets;
	}

	public void addStreet(Street street) {
		streets.add(street);
		street.setDistrict(this);
	}

	public void removeStreet(Street street) {
		streets.remove(street);
		street = null;
	}
} 

package cn.jbit.test2.bean;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name = "test_street2")
public class Street implements Serializable {

	private static final long serialVersionUID = -2865844315350365126L;

	@Id
	@GeneratedValue
	private Integer id;
	
	@Column(name = "name")
	private String name;

	@ManyToOne
	@JoinColumn(name = "district_id")
	private District district;

	public Street() {
		super();
	}

	public Street(Integer id, String name, District district) {
		super();
		this.id = id;
		this.name = name;
		this.district = district;
	}

	public Integer getId() {
		return id;
	}

	@SuppressWarnings("unused")
	private void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public District getDistrict() {
		return district;
	}

	public void setDistrict(District district) {
		this.district = district;
	}
}