Mybatis分页插件&注解模式

Mybatis分页插件

1. 分页插件的依赖

 
   
   
     com.github.pagehelper 
    
   
     pagehelper 
    
   
     5.1.10 
    
  

2. 在核心配置文件中配置分页查询

3. 分页代码

@Test public void testCutPage() { //查询employee表中的所有记录，每页显示2条记录 //1.设置分页 PageHelper.startPage(3,2); //2.查询 SqlSession session = MyBatisUtils.getSession(); EmployeeMapper employeeMapper = session.getMapper(EmployeeMapper.class); List 
  
    employeeList=employeeMapper.selectByExample(new EmployeeExample()); //3.把查询结果放到PageInfo中 PageInfo 
   
     pageInfo=new PageInfo 
    
      (employeeList); //4.可以从PageInfo中取出分页信息 long total=pageInfo.getTotal(); int totalPages=pageInfo.getPages(); List 
     
       employees= pageInfo.getList(); System.out.println("总记录数:"+total); System.out.println("总页数:"+totalPages); System.out.println("当前页:"+pageInfo.getPageNum()); System.out.println("每页记录数:"+pageInfo.getPageSize()); for (Employee employee : employees) { System.out.println(employee); } } 
      
     
    
  

Mybatis注解模式

1. 单标注解 

public interface WorkerMapper { @Insert("insert into worker(w_name,w_gender,w_age,w_salary) values(#{name},#{gender},#{age},#{salary})") public void saveWorker(Worker worker); @Update("update worker set w_name=#{name},w_gender=#{gender},w_age=#{age},w_salary=#{salary} where w_id=#{id}") public void updateWorker(Worker worker); @Delete("delete from worker where w_id=#{id}") public void deleteWorker(Integer id); @Select("select * from worker where w_id=#{id}") @Results({ @Result(column = "w_id",property = "id"), @Result(column = "w_name",property = "name"), @Result(column = "w_gender",property = "gender"), @Result(column = "w_age",property = "age"), @Result(column = "w_salary",property = "salary") }) public Worker getWorkerById(Integer id); @Select("select * from worker") @Results({ @Result(column = "w_id",property = "id"), @Result(column = "w_name",property = "name"), @Result(column = "w_gender",property = "gender"), @Result(column = "w_age",property = "age"), @Result(column = "w_salary",property = "salary") }) public List 
  
    getWorkers(); } 
  

2. 多表关系映射

EmployeeMapper注解映射

public interface EmployeeMapper { @Select("select * from employee where e_id=#{id}") @Results({ @Result(column = "e_id",property = "id"), @Result(column = "e_name",property = "name"), @Result(column = "e_gender",property = "gender"), @Result(property = "depart",javaType = Department.class,column = "e_depart_id", one = @One(select = "cn.offcn.mapper.DepartmentMapper.getDepartmentById",fetchType = FetchType.LAZY)) }) public Employee getEmployeeById(Integer id); @Select("select * from employee where e_depart_id=#{id}") @Results({ @Result(column = "e_id",property = "id"), @Result(column = "e_name",property = "name"), @Result(column = "e_gender",property = "gender") }) public List 
  
    getEmployeeByDepartId(Integer id); } 
  

DepartmentMapper映射

public interface DepartmentMapper { @Select("select * from department where d_id=#{id}") @Results({ @Result(column = "d_id",property = "id"), @Result(column = "d_name",property = "name"), @Result(property = "emps", column = "d_id", many = @Many(select = "cn.offcn.mapper.EmployeeMapper.getEmployeeByDepartId")) }) public Department getDepartmentById(Integer id); }