MyBatis学习笔记（十）注解映射

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);
}

  

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);