1 树状结构的设计
package com.bjsxt.hibernate; import java.util.HashSet;
import java.util.Set; import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany; @Entity
public class Org {
private int id;
private String name;
private Set<Org> children = new HashSet<Org>();
private Org parent;
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade=CascadeType.ALL, mappedBy="parent")
public Set<Org> getChildren() {
return children;
}
public void setChildren(Set<Org> children) {
this.children = children;
} @ManyToOne
@JoinColumn(name="parent_id")
public Org getParent() {
return parent;
}
public void setParent(Org parent) {
this.parent = parent;
}
}
@Test
public void testSave() {
Org o = new Org();
o.setName("总公司");
Org o1 = new Org();
o1.setName("分公司1");
Org o2 = new Org();
o2.setName("分公司2");
Org o11 = new Org();
o11.setName("分公司1下部门1");
Org o12 = new Org();
o12.setName("分公司1下部门2"); o.getChildren().add(o1);
o.getChildren().add(o2);
o1.getChildren().add(o11);
o1.getChildren().add(o12);
o11.setParent(o1);
o12.setParent(o1);
o1.setParent(o);
o2.setParent(o); Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(o); session.getTransaction().commit();
session.close();
}
@Test
public void testLoad() {
testSave();
Session session = sessionFactory.openSession();
session.beginTransaction();
Org o = (Org)session.load(Org.class, );
print(o, );
session.getTransaction().commit();
session.close(); } private void print(Org o, int level) { //输出
String preStr = "";
for(int i=; i<level; i++) { //缩进
preStr += "----";
}
System.out.println(preStr + o.getName());
for(Org child : o.getChildren()) {
print(child, level+);
}
}
Course
package com.bjsxt.hibernate; import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id; @Entity
public class Course {
private int id;
private String name;
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
} }
score
package com.bjsxt.hibernate; 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="score")
public class Score {
private int id;
private int score;
private Student student;
private Course course;
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
@ManyToOne
@JoinColumn(name="student_id")
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
} @ManyToOne
@JoinColumn(name="course_id")
public Course getCourse() {
return course;
}
public void setCourse(Course course) {
this.course = course;
} }
Student
package com.bjsxt.hibernate; import java.util.HashSet;
import java.util.Set; import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany; @Entity
public class Student {
private int id;
private String name;
private Set<Course> courses = new HashSet<Course>(); @ManyToMany
@JoinTable(name="score",
joinColumns=@JoinColumn(name="student_id", referencedColumnName="id"),
inverseJoinColumns=@JoinColumn(name="course_id", referencedColumnName="id")
)
public Set<Course> getCourses() {
return courses;
}
public void setCourses(Set<Course> courses) {
this.courses = courses;
}
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
} }
@Test
public void testSave() {
Student s = new Student();
s.setName("zhangsan");
Course c = new Course();
c.setName("java");
Score score = new Score();
score.setCourse(c);
score.setStudent(s); Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(s);
session.save(c);
session.save(score); session.getTransaction().commit();
session.close();
}
@Test
public void testLoad() {
testSave();
Session session = sessionFactory.openSession();
session.beginTransaction(); Student s = (Student)session.load(Student.class, );
for(Course c : s.getCourses()) {
System.out.println(c.getName());
} session.getTransaction().commit();
session.close(); }