JavaWeb page

We usually necessary parameter query is written Dao layer, but this is unreasonable in, Dao layer is only used to access and manipulate the database should not include other information, so a common practice to create a Page object, all the information into the paging inside

Page Object

public class Page {
    
    private List<Object> list;  //存放查询的数据
    private int currentPage;    //当前页数
    private int pageSize;       //每页显示的数据条数
    private int totalRecord;    //总数据条数
    private int totalPage;      //总页数
    
    //构造函数，两个参数
    public Page(int currentPage, int pageSize) {
        super();
        this.currentPage = currentPage;
        this.pageSize = pageSize;
    }
    
    public List<Object> getList() {
        return list;
    }
    public void setList(List<Object> list) {
        this.list = list;
    }
    public int getCurrentPage() {
        return currentPage;
    }
    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }
    public int getPageSize() {
        return pageSize;
    }
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }
    public int getTotalRecord() {
        return totalRecord;
    }
    public void setTotalRecord(int totalRecord) {
        this.totalRecord = totalRecord;
    }
    public int getTotalPage() {
        return totalPage;
    }
    public void setTotalPage(int totalPage) {
        this.totalPage = totalPage;
    }
}

Service Layer

public Page getPageData(int currentPage,int pageSize){
    
    Page page = new Page(currentPage,pageSize);
    
    //通过Dao层把查询数据放到Page对象中
    page.setTotalPage(pageDao.getTotalPage);
    page.setTotalRecord(pageDao.getTotalRecord);
    page.setList( pageDao.setList(currentPage,pageSize) );
    
    //返回Page给Web层
    return page;
}

Web layer

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    //获取前端传过来的参数
    int currentPage = Integer.parseInt( request.getParameter("currentPage") );
    int pageSize = Integer.parseInt( request.getParameter("pageSize") );
    
    //处理Page的Service对象
    PageService pageService = new PageService();
    
    //返回数据给前端，这里应该返回Json对象
    Page page = pageService.getPageData(currentPage, pageSize);
    
    //阿里巴巴有个开源的jar包，fastJson可以Bean和Json互转，具体操作可以看下面链接
    return JSON.toJSONString(page);
}

FastJson Click here to see the objects and Json Huzhuan

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