Hibernate 映射集合List的使用

做项目的过程中,对数据表建立一对多的关联关系时,以前都是用MyEclipse自动生成配置文件,数据集合都是使用默认生成的Set, Set是无序的,保存数据没有按顺序存储,而我需要把数据按保存时的顺序读取出来时,数据的顺序全乱了,看来想偷懒都不行,呵呵,修改hbm.xml配置文件,把Set换成list.
数据表语句,

create table student(
id int primary key,
name varchar(30),
age int,
sex varchar(8));

create table course(
id int primary key,
cid int ,
cname varchar(20),
idx int,
student_id int,
foreign key course(student_id) references student(id)
);

映射文件与持久类

Student.hbm.xml

1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
4 
7 <hibernate-mapping>
8     <class name="com.dragon.datamodel.Student" table="student" >
9         <id name="id" type="java.lang.Integer">
10             <column name="id" />
11             <generator class="increment" />
12         </id>
13         <property name="name" type="java.lang.String">
14             <column name="name" length="30" not-null="true" />
15         </property>
16         <property name="age" type="java.lang.Integer">
17             <column name="age" />
18         </property>
19         <property name="sex" type="java.lang.String">
20             <column name="sex" length="8" />
21         </property>
22
23         <list name="courses" table="course" cascade="all">
24            <key column="student_id"  ></key>
25            
26            <index column="idx" type="java.lang.Integer"></index>
27            <one-to-many class="com.dragon.datamodel.Course" />
28         </list>
29
30     </class>
31 </hibernate-mapping>
32

Student.java

  1 package com.dragon.datamodel;
  2
  3
  4
  5 import java.util.ArrayList;
  6
  7 import java.util.List;
  8
  9
10
11 /**
12
13  * Student generated by MyEclipse Persistence Tools
14
15  */
16
17
18
19 public class Student implements java.io.Serializable {
20
21
22
23     // Fields
24
25
26
27     /**
28
29      *
30
31      */
32
33     private static final long serialVersionUID = 1L;
34
35
36
37     private Integer id;
38
39
40
41     private String name;
42
43
44
45     private Integer age;
46
47
48
49     private String sex;
50
51
52
53     private List courses = new ArrayList();
54
55
56
57     // Constructors
58
59
60
61     /** default constructor */
62
63     public Student() {
64
65     }
66
67
68
69     /** minimal constructor */
70
71     public Student(String name) {
72
73         this.name = name;
74
75     }
76
77
78
79     /** full constructor */
80
81     public Student(String name, Integer age, String sex) {
82
83         this.name = name;
84
85         this.age = age;
86
87         this.sex = sex;
88
89     }
90
91
92
93     // Property accessors
94
95
96
97     public Integer getId() {
98
99         return this.id;
100
101     }
102
103
104
105     public void setId(Integer id) {
106
107         this.id = id;
108
109     }
110
111
112
113     public String getName() {
114
115         return this.name;
116
117     }
118
119
120
121     public void setName(String name) {
122
123         this.name = name;
124
125     }
126
127
128
129     public Integer getAge() {
130
131         return this.age;
132
133     }
134
135
136
137     public void setAge(Integer age) {
138
139         this.age = age;
140
141     }
142
143
144
145     public String getSex() {
146
147         return this.sex;
148
149     }
150
151
152
153     public void setSex(String sex) {
154
155         this.sex = sex;
156
157     }
158
159
160
161     public List getCourses() {
162
163         return courses;
164
165     }
166
167
168
169     public void setCourses(List courses) {
170
171         this.courses = courses;
172
173     }
174
175
176
177     public void addCourses(Course course){
178
179         this.courses.add(course);
180
181     }
182
183
184
185
186
187 }

Course.hbm.xml

Course.java

1 package com.dragon.datamodel;
2
3 /**
4  * Course generated by MyEclipse Persistence Tools
5  */
6
7 public class Course implements java.io.Serializable {
8
9     // Fields
10
11     /**
12      *
13      */
14     private static final long serialVersionUID = 1L;
15
16     private Integer id;
17
18     private Integer cid;
19
20     private String cname;
21
22 //    private Integer studentId;
23
24     // Constructors
25
26
27     /** default constructor */
28     public Course() {
29     }
30
31     /** full constructor */
32     public Course(Integer cid, String cname, Integer studentId) {
33         this.cid = cid;
34         this.cname = cname;
35 //        this.studentId = studentId;
36     }
37
38     // Property accessors
39
40     public Integer getId() {
41         return this.id;
42     }
43
44     public void setId(Integer id) {
45         this.id = id;
46     }
47
48     public Integer getCid() {
49         return this.cid;
50     }
51
52     public void setCid(Integer cid) {
53         this.cid = cid;
54     }
55
56     public String getCname() {
57         return this.cname;
58     }
59
60     public void setCname(String cname) {
61         this.cname = cname;
62     }
63
64 //    public Integer getStudentId() {
65 //        return this.studentId;
66 //    }
67 //
68 //    public void setStudentId(Integer studentId) {
69 //        this.studentId = studentId;
70 //    }
71
72 }

测试类
TestList.java

1 /**
2  *
3  */
4 package com.test;
5
6 import java.util.List;
7
8 import org.hibernate.Session;
9 import org.hibernate.Transaction;
10 import org.junit.After;
11 import org.junit.Before;
12 import org.junit.Test;
13
14 import com.dragon.datamodel.Course;
15 import com.dragon.datamodel.HibernateSessionFactory;
16 import com.dragon.datamodel.Student;
17
18 /**
19  * @author dragon
20  *
21  */
22 public class TestList {
23
24     private Session session;
25     private Transaction tx;
26
27     @Before
28     public void setup(){
29         session = HibernateSessionFactory.getSession();
30         tx = session.beginTransaction();
31     }
32
33 //    @Test
34     public void saveStundetInfo(){
35         Student stu = new Student();
36         stu.setName("dragon");
37         stu.setAge(23);
38         stu.setSex("男");
39         String k ;
40
41         Course c1 = new Course();
42         c1.setCid(3);
43         c1.setCname("j2ee 应用");
44
45         Course c2 = new Course();
46         c2.setCid(21);
47         c2.setCname("C# 基础");
48
49         Course c3 = new Course();
50         c3.setCid(22);
51         c3.setCname("软件工程");
52
53         stu.addCourses(c1);
54         stu.addCourses(c2);
55         stu.addCourses(c3);
56
57         session.save(stu);
58
59
60
61     }
62
63
64    @Test
65    public void LoadStudentInfo(){
66        List list = session.createQuery("from Student").list();
67
68        for (int i =0; i < list.size(); i++){
69            Student stu = (Student) list.get(i);
70            System.out.println(stu.getName());
71            List courses = stu.getCourses();
72            for (int j = 0; j < courses.size(); j++){
73                Course cors = (Course) courses.get(j);
74                System.out.print("    "+cors.getCname());
75            }
76            System.out.println();
77        }
78
79    }
80
81
82
83     @After
84     public void closeSession(){
85         tx.commit();
86         session.close();
87     }
88
89 }
90

Hibernate 映射集合List的使用

你可能感兴趣的:(Hibernate 映射集合List的使用)