示例：

設計代碼，實現在數據庫中建student表、course表、和score表，展現三者關系

student表：id、name

course表：id、name

score表：id、score、student_id、course_id

三張表的關聯關系如下：

設計思路：

1.首先創建Student實體類和Course實體類

會自動創建中間表，通過@JoinTable注解，設置中間表名為“score”，屬性名分別為“student_id”和“course_id”

@ManyToMany@JoinTable(name="score",    joinColumns={@JoinColumn(name="student_id")},    inverseJoinColumns={@JoinColumn(name="course_id")})

2.創建實體類Score

    PRivate int id;     private int score;     private Student student;     private Course course;

根據步驟1中創建的中間表，通過@Table注解設置表名為“score”，

通過@ManyToOne注解設置屬性名分別為“student_id”和“course_id”

3.Junit測試類

@Testpublic void test() {    new SchemaExport(new Configuration().configure()).create(true, true);}

具體實現代碼如下：

1.Student類

@Entitypublic class Student {private int id;private String name;private Set<Course> courses = new HashSet<Course>();@Id@GeneratedValuepublic 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;}@ManyToMany@JoinTable(name="score",                                                 //中間表名joinColumns={@JoinColumn(name="student_id")},            //屬性名inverseJoinColumns={@JoinColumn(name="course_id")})      //屬性名public Set<Course> getCourses() {return courses;}public void setCourses(Set<Course> courses) {this.courses = courses;}}

2.Course類

@Entitypublic class Course {private int id;private String name;@Id@GeneratedValuepublic 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;}}

3.Score類

@Entity@Table(name="score")      //對應中間表名public class Score {private int id;private int score;private Student student;private Course course;@Id@GeneratedValuepublic 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")    //對應屬性名public Student getStudent() {return student;}public void setStudent(Student student) {this.student = student;}@ManyToOne()@JoinColumn(name="course_id")    //對應屬性名public Course getCourse() {return course;}public void setCourse(Course course) {this.course = course;}}

4.存儲一條數據

@Testpublic void testsave() {session session = sf.getCurrentSession();session.beginTransaction();Student s = new Student();s.setName("lisi");Course c = new Course();c.setName("c++");Score score = new Score();score.setStudent(s);score.setCourse(c);//score.setScore(90);  //若不設置，默認為0session.save(s);session.save(c);session.save(score);session.getTransaction().commit();}

注意：

create table score (id integer not null, score integer not null, course_id integer, student_id integer not null auto_increment, primary key (student_id, course_id)) 運行程序，會發現通過程序自動建的score表是有問題的。 我們想要的是，id為主鍵，且自增 而結果是，student_id和course_id為聯合主鍵，且student_id自增 這是hibernate自身的bug，所以應該手動去數據庫中，修改表的結構