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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