java分页

package entity;



public class Page { //记录当前页的状态信息

private int num; //当前页号，采用自然数计数 1,2,3,...

private int size; //一页显示多少个数据

private int rowCount; //记录的总数目（一共有多少个数据）

private int pageCount; //页面总数（n页）

private int startRow; //当前页开始行号，第一行是0行 

private int first=1; //第一页 页号

private int last; //最后页 页号

private int next; //下一页 页号

private int prev; //前一页 页号

private int start; // 页号式导航, 起始页号

private int end; // 页号式导航, 结束页号

private int numCount = 4; // 页号式导航, 最多显示页号数量为numCount+1;这里显示5页。



public Page(int size, String str_num, int rowCount) {



int num = 1;

if (str_num != null) { //str_num，起始记录号

num = Integer.parseInt(str_num);

}

this.num = num;

this.size = size;

this.rowCount = rowCount;

this.pageCount = (int) Math.ceil((double) rowCount / size); //**获取页数的总数,ceil是进1取整

this.num = Math.min(this.num, pageCount); //当前页号最大值为pageCount

this.num = Math.max(1, this.num); //当前页号最小值为1

this.startRow = (this.num-1) * size; //开始行号为 0行

this.last = this.pageCount; //最后一页页号为pageCount

this.next = Math.min(this.pageCount, this.num+1); //最后一页为pageCount或者为当前页+1

this.prev = Math.max(1, this.num-1); //最前一页为1或者为当前页-1



// 计算page 控制

//当点击7的时候只出现5到9，当点击8的时候，只出现6到10

//若是出现1-5或者6-10，则可改为:if((this.num+1)%(numCount+1)==0){

//start=(this.num+1)%(numCount+1)-1*(numCount+1)+1;}

//else{ start=this.num/(numCount+1)*(numCount+1)+1;}

//比如15和14

//本页显示页号从多少页开始，eg:7-4/2=5(第七页就是从第五页开始)

start = Math.max(this.num - numCount/2, first); 



//本页显示页号在多少页号结束 eg:5+4=9（若本页是第七页，则本页开始页为5，结束页为9，每页显示5个）

end = Math.min(start + numCount, last); 

if (end - start < numCount) { //如果记录数小于4

start = Math.max(end - numCount, 1); //开始页为1和结束页号-记录数的最大值

}

}



public int getNum() {

return num;

}

public void setNum(int num) {

this.num = num;

}

public int getSize() {

return size;

}

public void setSize(int size) {

this.size = size;

}

public int getRowCount() {

return rowCount;

}

public void setRowCount(int rowCount) {

this.rowCount = rowCount;

}

public int getPageCount() {

return pageCount;

}

public void setPageCount(int pageCount) {

this.pageCount = pageCount;

}

public int getStartRow() {

return startRow;

}

public void setStartRow(int startRow) {

this.startRow = startRow;

}

public int getFirst() {

return first;

}

public void setFirst(int first) {

this.first = first;

}

public int getLast() {

return last;

}

public void setLast(int last) {

this.last = last;

}

public int getNext() {

return next;

}

public void setNext(int next) {

this.next = next;

}

public int getPrev() {

return prev;

}

public void setPrev(int prev) {

this.prev = prev;

}

public int getStart() {

return start;

}



public void setStart(int start) {

this.start = start;

}



public int getEnd() {

return end;

}



public void setEnd(int end) {

this.end = end;

}



public int getNumCount() {

return numCount;

}



public void setNumCount(int numCount) {

this.numCount = numCount;

}

}