MyBatis学习笔记（十）注解映射

１.普通映射

[html] view plain copy

1. @Select("select * from mybatis_Student where id=#{id}")  
2. public Student getStudent(int id);  
3. @Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")  
4. public int insert(Student student);  
5. @Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")  
6. public int update(Student student);  
7. @Delete("delete from mybatis_Student where id=#{id}")  
8. public int delete(int id);  

２.结果集映射

[html] view plain copy

1. @Select("select * from mybatis_Student")  
2. @Results({  
3.     @Result(id=true,property="id",column="id"),  
4.     @Result(property="name",column="name"),  
5.     @Result(property="age",column="age")  
6. })  
7. public List<Student> getAllStudents();  

３.关系映射

1),一对一

[html] view plain copy

1. @Select("select * from mybatis_Student")  
2. @Results({  
3.     @Result(id=true,property="id",column="id"),  
4.     @Result(property="name",column="name"),  
5.     @Result(property="age",column="age"),  
6.     @Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
7. })  
8. public List<Student> getAllStudents();  

2)一对多

[html] view plain copy

1. package com.skymr.mybatis.mappers;  
2.   
3. import org.apache.ibatis.annotations.Many;  
4. import org.apache.ibatis.annotations.Result;  
5. import org.apache.ibatis.annotations.Results;  
6. import org.apache.ibatis.annotations.Select;  
7.   
8. import com.skymr.mybatis.model.Grade;  
9.   
10. public interface Grade2Mapper {  
11.   
12.     @Select("select * from mybatis_grade where id=#{id}")  
13.     @Results({  
14.         @Result(id=true,column="id",property="id"),  
15.         @Result(column="grade_name",property="gradeName"),  
16.         @Result(property="students",column="id",many=@Many(select="com.skymr.mybatis.mappers.Student2Mapper.getStudentsByGradeId"))  
17.     })  
18.     public Grade getGrade(int id);  
19. }  

[html] view plain copy

1. package com.skymr.mybatis.mappers;  
2.   
3. import java.util.List;  
4.   
5. import org.apache.ibatis.annotations.Delete;  
6. import org.apache.ibatis.annotations.Insert;  
7. import org.apache.ibatis.annotations.One;  
8. import org.apache.ibatis.annotations.Result;  
9. import org.apache.ibatis.annotations.Results;  
10. import org.apache.ibatis.annotations.Select;  
11. import org.apache.ibatis.annotations.Update;  
12.   
13. import com.skymr.mybatis.model.Student;  
14.   
15. public interface Student2Mapper {  
16.   
17.     @Select("select * from mybatis_Student where id=#{id}")  
18.     public Student getStudent(int id);  
19.     @Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")  
20.     public int insert(Student student);  
21.     @Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")  
22.     public int update(Student student);  
23.     @Delete("delete from mybatis_Student where id=#{id}")  
24.     public int delete(int id);  
25.       
26.     @Select("select * from mybatis_Student")  
27.     @Results({  
28.         @Result(id=true,property="id",column="id"),  
29.         @Result(property="name",column="name"),  
30.         @Result(property="age",column="age"),  
31.         @Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
32.     })  
33.     public List<Student> getAllStudents();  
34.     @Select("select * from mybatis_Student where grade_id=#{gradeId}")  
35.         @Results({  
36.         @Result(id=true,property="id",column="id"),  
37.         @Result(property="name",column="name"),  
38.         @Result(property="age",column="age"),  
39.         @Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
40.     })  
41.     public List<Student> getStudentsByGradeId(int gradeId);  
42. }  

４.动态sql注解映射

provider类

[html] view plain copy

1. package com.skymr.mybatis.mappers.provider;  
2.   
3. import java.util.Map;  
4.   
5. import org.apache.ibatis.jdbc.SQL;  
6.   
7. import com.skymr.mybatis.model.Student;  
8.   
9. public class StudentDynaSqlProvider {  
10.   
11.     public String insertStudent(final Student student){  
12.         return new SQL(){  
13.             {  
14.                 INSERT_INTO("mybatis_Student");  
15.                 if(student.getName() != null){  
16.                     VALUES("name","#{name}");  
17.                 }  
18.                 if(student.getAge() > 0){  
19.                     VALUES("age","#{age}");  
20.                 }  
21.             }  
22.         }.toString();  
23.     }  
24.       
25.     public String updateStudent(final Student student){  
26.         return new SQL(){  
27.             {  
28.                 UPDATE("mybatis_Student");  
29.                 if(student.getName() != null){  
30.                     SET("name=#{name}");  
31.                 }  
32.                 if(student.getAge() > 0){  
33.                     SET("age=#{age}");  
34.                 }  
35.                 WHERE("id=#{id}");  
36.             }  
37.         }.toString();  
38.     }  
39.       
40.     public String getStudent(final Map<String,Object> map){  
41.         return new SQL(){  
42.             {  
43.                 SELECT("*");  
44.                 FROM("mybatis_Student");  
45.                 if(map.containsKey("name")){  
46.                     WHERE("name like #{name}");  
47.                 }  
48.                 if(map.containsKey("age")){  
49.                     WHERE("age=#{age}");  
50.                 }  
51.             }  
52.         }.toString();  
53.     }  
54.       
55.     public String deleteStudent(){  
56.         return new SQL(){  
57.             {  
58.                 DELETE_FROM("mybatis_Student");  
59.                 WHERE("id=#{id}");  
60.             }  
61.         }.toString();  
62.     }  
63. }  

Mapper接口

[html] view plain copy

1. @SelectProvider(type=StudentDynaSqlProvider.class,method="getStudent")  
2. public List<Student> getStudents(Map<String,Object> map);