jqgrid java服务器端分页

Question

I'm trying to add server side sorting to my grid, so I added this:

onPaging : function(which_button) {
                 _$("#myGrid").setGridParam({datatype: "xml"});
                _$("#myGrid").trigger('reloadGrid');
            }

and when ever I clicked the next page button it went to my server and loaded the grid again, so I see the records from the first page again. my question is how do I connect the data about the grid records and my server? Is there a full example of server side paging? what else do I need to pass into my server inorder to get the currect records for the next page? what do i neeed to add to my web page and what to the server page?

Any help will be appritiated,

Thank's In Advance.

Answer 1

Please confirm are you doing server side sorting or server side paging. From the question I understand that you are trying to retrieve the next page data from the server on click of next/prev button in the grid. If your objective is just to get the paging data then below logic would help. If you are interested in server side sort + server side paging a similar approach needs to be followed for that.

Logic for Server side paging: Lets assume you have total of 1000 records which has to be displayed as 50 records per page. I am assuming that you only pull the 1st 50 records while displaying the records in first page and then on click of next button you want to retrieve the next 50 records to be displayed in the grid from the database.

You don't need the onPaging : function. Just setting paging:true will suffice.

Have following variables in the java class with getter and setter

// Total pages
    private Integer total = 0;
     //get how many rows we want to have into the grid - rowNum attribute in the grid
    private Integer rows = 0;
    //Get the requested page. By default grid sets this to 1.
    private Integer page = 0;
    // All Record
    private Integer records = 0;
    // sorting order ascending or descending
    private String sord;
    // get index row - i.e. user click to sort
    private String sidx;
/**
     * @return the total
     */
    public Integer getTotal() {
        return total;
    }

    /**
     * @param total the total to set
     */
    public void setTotal(Integer total) {
        this.total = total;
    }

    /**
     * @return the rows
     */
    public Integer getRows() {
        return rows;
    }

    /**
     * @param rows the rows to set
     */
    public void setRows(Integer rows) {
        this.rows = rows;
    }

    /**
     * @return the page
     */
    public Integer getPage() {
        return page;
    }

    /**
     * @param page the page to set
     */
    public void setPage(Integer page) {
        this.page = page;
    }

    /**
     * @return the records
     */
    public Integer getRecords() {
        return records;
    }

    /**
     * @param records the records to set
     */
    public void setRecords(Integer records) {
        this.records = records;

        if(this.records > 0 && this.rows > 0){
            this.total = (int)Math.ceil((double) this.records/(double) this.rows);
        }else{
            this.total = 0;
        }
    }

    /**
     * @return the sord
     */
    public String getSord() {
        return sord;
    }

    /**
     * @param sord the sord to set
     */
    public void setSord(String sord) {
        this.sord = sord;
    }

    /**
     * @return the sidx
     */
    public String getSidx() {
        return sidx;
    }

    /**
     * @param sidx the sidx to set
     */
    public void setSidx(String sidx) {
        this.sidx = sidx;
    }

After that what you need is some calculations to set the fields for the grid as per retrieved records.

// Assuming you have 1000 records in total. This should be set dynamically. For time being it is hardcoded to 1000.

setRecords(1000);
// for first time when we have page=0, it should 
// be page =1;
// If last page is required and if page no crosses total count
                int displayCount = count/rows;
                int remainder = count%rows;
                page = (page<=displayCount?page:count==0?0:remainder==0?displayCount:displayCount+1);


                int to = (getRows() * getPage());
                int from = to - getRows();

                if (to > getRecords()) to = getRecords();

                if (from > to) {
                    from = 0;
                    page = 1;
                }

setTotal((int) Math.ceil((double) getRecords() / (double) getRows()));

                if(getTotal() == 0) page =0;