MyBatis注解映射

淡淡的烟草味﹌ 2022-05-29 10:52 228阅读 0赞

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

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);