hibernate生成自定义主键(类似user000000001——可自己通过配置文件配置)

生成主键的类

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 1 package action;

 2 

 3 import java.io.Serializable;

 4 import java.util.List;

 5 import java.util.Properties;

 6 

 7 import org.hibernate.HibernateException;

 8 import org.hibernate.MappingException;

 9 import org.hibernate.dialect.Dialect;

10 import org.hibernate.engine.QueryParameters;

11 import org.hibernate.engine.SessionImplementor;

12 import org.hibernate.id.Configurable;

13 import org.hibernate.id.IdentifierGenerator;

14 import org.hibernate.type.Type;

15 /**

16  * 

17 * 类名称：      GeneratePK   

18 * 类描述：     在hibernate的基础上自动生成自定义的主键

19 * 创建人：     andy_lj  

20 * 创建时间：2012-08-10 上午11:40:50     

21 * 修改备注：   

22 * @version

23  */

24 public class GeneratePK implements Configurable, IdentifierGenerator {

25     public String sign;// user000000001中的user

26     public String classname; //实体类的类名

27     public String pk;//主键名字

28     public String idLength;//user000000001的长度

29     

30     /**

31      * 取得User.hbm.xml中的自定义的值

32      */

33     @Override

34     public void configure(Type arg0, Properties arg1, Dialect arg2)

35             throws MappingException {

36         this.classname = arg1.getProperty("classname");

37         this.pk = arg1.getProperty("pk");

38         this.sign = arg1.getProperty("sign");

39         this.idLength = arg1.getProperty("idLength");

40     }

41     /**

42      * 生成主键

43      */

44     @Override

45     public Serializable generate(SessionImplementor arg0, Object arg1)

46             throws HibernateException {

47          //获得主键的长度

48         int leng = Integer.valueOf(idLength);

49         //需要查询数据库中最大的ID号

50         StringBuffer sql = new StringBuffer("select max(a.").append(pk)

51                                                             .append(") from ")

52                                                             .append(classname)

53                                                             .append(" as a where a.")

54                                                             .append(pk)

55                                                             .append(" like '")

56                                                             .append(sign)

57                                                             .append("%'");

58         QueryParameters qp = new QueryParameters();

59         List ls = arg0.list(sql.toString(), qp);

60         String max = (String) ls.get(0);

61         int i = 0;

62         //如果是第一次添加记录那么就是类似user000000001

63         if (max == null || max.trim().equals("")) {

64             max = "1";

65             for(; i < leng-sign.length()-1; i++) {

66                 max = "0" + max;

67             }

68             i = 0;

69             return sign + max;

70         }//不是第一次的操作,并且记录的长度没有超过从配置文件中读取的长度

71         else if(max != null && max.length() <= leng) {

72             max = max.replaceAll(sign, "");

73             Integer imax = Integer.parseInt(max) + 1;

74             String returnnum = String.valueOf(imax);

75             int zero = leng-sign.length()-returnnum.length();

76             for(; i < zero; i++) {

77                 returnnum = "0" + returnnum;

78             }

79             i = 0;

80             return sign + returnnum;

81         }//不是第一次的操作,记录的长度超过了从配置文件中读取的长度

82         else {

83             leng = max.length();

84             max = max.replaceAll(sign, "");

85             Integer imax = Integer.parseInt(max) + 1;

86             String returnnum = String.valueOf(imax);

87             int zero = leng-sign.length()-returnnum.length();

88             for(; i < zero; i++) {

89                 returnnum = "0" + returnnum;

90             }

91             return sign + returnnum;

92         }

93     }

94 

95 }

 

配置文件：User.hbm.xml

View Code

 1 <?xml version="1.0" encoding="UTF-8"?>

 2 <!DOCTYPE hibernate-mapping PUBLIC 

 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

 4     "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

 5 <hibernate-mapping package="entity">

 6     <class name="User" table="TEMP" lazy="false">

 7         <id name="userId" column="userId">

 8             <generator class="action.GeneratePK" >

 9               <param name="classname">User</param>

10               <param name="pk">userId</param>

11               <param name="sign">poli</param>

12               <param name="idLength">13</param>

13             </generator>

14         </id>

15         <property name="name" column="name" />

16         <property name="age" column="age" type="integer"/>

17         <property name="address" column="address" />

18     </class>

19 </hibernate-mapping>