Java初学者,学习ssh框架的时候,遇到分页问题,控制台提示
空指针,DepartmentServiceImpl实现类中提示24行有错误,我觉得是当前页数
无法获取,求大神解决一下。
错误信息
DepartmentServiceImpl实现类的代码为
package com.ssh.employee.service.impl;
import java.util.List;
import com.ssh.employee.dao.DepartmentDao;
import com.ssh.employee.entity.Department;
import com.ssh.employee.entity.PageBean;
import com.ssh.employee.service.DepartmentService;
public class DepartmentServiceImpl implements DepartmentService{
//注入Dao层的类
private DepartmentDao departmentDao;
public void setDepartmentDao(DepartmentDao departmentDao) {
this.departmentDao = departmentDao;
}
@Override
public PageBean<Department> findByPage(Integer currPage) {
// TODO Auto-generated method stub
PageBean<Department> pageBean = new PageBean<Department>();
//封装当前页数
System.out.println("service 执行了");
pageBean.setCurrPage(currPage);
//封装每页显示记录数
int pageSize= 3;
pageBean.setPageSize(pageSize);
//封装总记录数
int totalCount = departmentDao.findCount();
pageBean.setTotalCount(totalCount);
System.out.println(pageBean.getTotalCount());//这个可以显示
//封装总页数
double tc = totalCount;
Double num = Math.ceil(tc/pageSize);
pageBean.setTotalPage(num.intValue());
//封装每页显示的数据
int begin = (currPage - 1) * pageSize;
List<Department> list = departmentDao.findByPage(begin,pageSize);
System.out.println("service 执行了");
pageBean.setList(list);
return pageBean;
}
}