java 中MyBatis注解映射的实例详解
１.普通映射
@Select("select * from mybatis_Student where id=#{id}")
public Student getStudent(int id);
@Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")
public int insert(Student student);
@Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")
public int update(Student student);
@Delete("delete from mybatis_Student where id=#{id}")
public int delete(int id);
２.结果集映射
@Select("select * from mybatis_Student")
@Results({
@Result(id=true,property="id",column="id"),
@Result(property="name",column="name"),
@Result(property="age",column="age")
})
public List<Student> getAllStudents();
３.关系映射
1),一对一
@Select("select * from mybatis_Student")
@Results({
@Result(id=true,property="id",column="id"),
@Result(property="name",column="name"),
@Result(property="age",column="age"),
@Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))
})
public List<Student> getAllStudents();
2)一对多
package com.skymr.mybatis.mappers;
import org.apache.ibatis.annotations.Many;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import com.skymr.mybatis.model.Grade;
public interface Grade2Mapper {
@Select("select * from mybatis_grade where id=#{id}")
@Results({
@Result(id=true,column="id",property="id"),
@Result(column="grade_name",property="gradeName"),
@Result(property="students",column="id",many=@Many(select="com.skymr.mybatis.mappers.Student2Mapper.getStudentsByGradeId"))
})
public Grade getGrade(int id);
}
Java代码
package com.skymr.mybatis.mappers;
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.One;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import com.skymr.mybatis.model.Student;
public interface Student2Mapper {
@Select("select * from mybatis_Student where id=#{id}")
public Student getStudent(int id);
@Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")
public int insert(Student student);
@Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")
public int update(Student student);
@Delete("delete from mybatis_Student where id=#{id}")
public int delete(int id);
@Select("select * from mybatis_Student")
@Results({
@Result(id=true,property="id",column="id"),
@Result(property="name",column="name"),
@Result(property="age",column="age"),
@Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))
})
public List<Student> getAllStudents();
@Select("select * from mybatis_Student where grade_id=#{gradeId}")
@Results({
@Result(id=true,property="id",column="id"),
@Result(property="name",column="name"),
@Result(property="age",column="age"),
@Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))
})
public List<Student> getStudentsByGradeId(int gradeId);
}
４.动态sql注解映射
provider类
package com.skymr.mybatis.mappers.provider;
import java.util.Map;
import org.apache.ibatis.jdbc.SQL;
import com.skymr.mybatis.model.Student;
public class StudentDynaSqlProvider {
public String insertStudent(final Student student){
return new SQL(){
{
INSERT_INTO("mybatis_Student");
if(student.getName() != null){
VALUES("name","#{name}");
}
if(student.getAge() > 0){
VALUES("age","#{age}");
}
}
}.toString();
}
public String updateStudent(final Student student){
return new SQL(){
{
UPDATE("mybatis_Student");
if(student.getName() != null){
SET("name=#{name}");
}
if(student.getAge() > 0){
SET("age=#{age}");
}
WHERE("id=#{id}");
}
}.toString();
}
public String getStudent(final Map<String,Object> map){
return new SQL(){
{
SELECT("*");
FROM("mybatis_Student");
if(map.containsKey("name")){
WHERE("name like #{name}");
}
if(map.containsKey("age")){
WHERE("age=#{age}");
}
}
}.toString();
}
public String deleteStudent(){
return new SQL(){
{
DELETE_FROM("mybatis_Student");
WHERE("id=#{id}");
}
}.toString();
}
}
Mapper接口
@SelectProvider(type=StudentDynaSqlProvider.class,method="getStudent") public List<Student> getStudents(Map<String,Object> map);
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