Mybtais使用注解配置sql映射器

注解不支持所有的功能一般开发使用xml配置文件

查询直接返回Student 直接用@select

public interface StudentMapper {

	@Insert("insert into t_student values(null,#{name},#{age})")
	public int insertStudent(Student student);
	
	@Update("update t_student set name=#{name},age=#{age} where id=#{id}")
	public int updateStudent(Student student);
	
	@Delete("delete from t_student where id=#{id}")
	public int deleteStudent(int id);
	
	@Select("select * from t_student where id=#{id}")
	public Student getStudentById(Integer id);
}

返回集合

	@Select("select * from t_student")
	@Results(
			{
				@Result(id=true,column="id",property="id"),
				@Result(column="name",property="name"),
				@Result(column="age",property="age")
			}
	)
	public List<Student> findStudents();

一对一关联查询

定义结果集

	@Select("select * from t_student where id=#{id}")
	@Results(
			{
				@Result(id=true,column="id",property="id"),
				@Result(column="name",property="name"),
				@Result(column="age",property="age"),
				@Result(column="addressId",property="address",one=@One(select="com.java1234.mappers.AddressMapper.findById"))
			}
	)
	public Student selectStudentWithAddress(int id);


public interface AddressMapper {

	@Select("select * from t_address where id=#{id}")
	public Address findById(Integer id);

}

一对多关联查询

	
public class Student {

	private Integer id;
	private String name;
	private Integer age;
	private Grade grade;
}

public class Grade {

	private Integer id;
	private String gradeName;
	private List<Student> students;
}

@Select("select * from t_student where gradeId=#{gradeId}")
	@Results(
			{
				@Result(id=true,column="id",property="id"),
				@Result(column="name",property="name"),
				@Result(column="age",property="age"),
				@Result(column="addressId",property="address",one=@One(select="com.java1234.mappers.AddressMapper.findById"))
			}
	)
	public Student selectStudentByGradeId(int gradeId);
	
	@Select("select * from t_student where id=#{id}")
	@Results(
			{
				@Result(id=true,column="id",property="id"),
				@Result(column="name",property="name"),
				@Result(column="age",property="age"),
				@Result(column="addressId",property="address",one=@One(select="com.java1234.mappers.AddressMapper.findById")),
				@Result(column="gradeId",property="grade",one=@One(select="com.java1234.mappers.GradeMapper.findById"))
			}
	)
	public Student selectStudentWithAddressAndGrade(int id);
}

public interface GradeMapper {

	@Select("select * from t_grade where id=#{id}")
	@Results(
			{
				@Result(id=true,column="id",property="id"),
				@Result(column="gradeName",property="gradeName"),
				@Result(column="id",property="students",many=@Many(select="com.java1234.mappers.StudentMapper.selectStudentByGradeId"))
			}
	)
	public Grade findById(Integer id);

}

动态sql

public class StudentDynaSqlProvider {

	public String insertStudent(final Student student){
		return new SQL(){
			{
				INSERT_INTO("t_student");
				if(student.getName()!=null){
					VALUES("name", "#{name}");
				}
				if(student.getAge()!=null){
					VALUES("age", "#{age}");
				}
			}
		}.toString();
	}
}

public interface StudentMapper {

	@InsertProvider(type=StudentDynaSqlProvider.class,method="insertStudent")
	public int insertStudent(Student student);
}

public String updateStudent(final Student student){
		return new SQL(){
			{
				UPDATE("t_student");
				if(student.getName()!=null){
					SET("name=#{name}");
				}
				if(student.getAge()!=null){
					SET("age=#{age}");
				}
				WHERE("id=#{id}");
			}
		}.toString();
	}
}

	@UpdateProvider(type=StudentDynaSqlProvider.class,method="updateStudent")
	public int updateStudent(Student student);

public String deleteStudent(){
		return new SQL(){
			{
				DELETE_FROM("t_student");
				WHERE("id=#{id}");
			}
		}.toString();
	}

	@DeleteProvider(type=StudentDynaSqlProvider.class,method="deleteStudent")
	public int deleteStudent(int id);

	public String getStudentById(){
		return new SQL(){
			{
				SELECT("*");
				FROM("t_student");
				WHERE("id=#{id}");
			}
		}.toString();
	}

	@SelectProvider(type=StudentDynaSqlProvider.class,method="getStudentById")
	public Student getStudentById(Integer id);

	public String findStudents(final Map<String,Object> map){
		return new SQL(){
			{
				SELECT("*");
				FROM("t_student");
				StringBuffer sb=new StringBuffer();
				if(map.get("name")!=null){
					sb.append(" and name like '"+map.get("name")+"'");
				}
				if(map.get("age")!=null){
					sb.append(" and age="+map.get("age"));
				}
				if(!sb.toString().equals("")){
					WHERE(sb.toString().replaceFirst("and", ""));					
				}
			}
		}.toString();
	}

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

扫描二维码关注公众号，回复： 2886057 查看本文章