SSM实现简单后台分页

1.简单思路

　　这是最常见的分页格式，分析一下我们需要传什么数据给前端吧！首先是左边下面的总共几条记录，然后是右边的当前页面，然后就是一些你所需要展示的数据。对了每页显示多少条是不也得控制下，下面的显示页码数,这里显示了五条（1，2，3，4，5），你也可以选择只显示三条（1，2，3）。

2.构造传给页面的POJO

package com.Dy.Pojo;

import java.util.List;

/**

 * 分页信息

 *

 * @author 小丁同学

 *

 */

public class PageInfo<T> {

    // 你页面需要展示的集合

    private List<T> list;

    // 显示的总记录数

    private Integer totalNum;

    // 总页数

    private Integer totalPage;

    // 当前页

    private Integer currentPage;

    // 每页显示的数目 (为了防止硬编码可以写在配置文件中)

    private Integer pageSize;

    // 下面两个就是显示的页码 比如start为1 pageNo为5，那么显示的页码数就是1，2，3，4，5

    private Integer start;

    private Integer pageNo;

    public PageInfo(Integer totalNum, Integer currentPage, Integer pageSize, Integer pageNo) {

        this.totalNum = totalNum;

        this.currentPage = currentPage;

        this.pageSize = pageSize;

        /*this.pageNo = pageNo;*/

        // 计算总页数

        if (totalNum % this.pageSize == 0)

            this.totalPage = totalNum / this.pageSize;

        else

            this.totalPage = (totalNum / this.pageSize) + 1;

        this.start = currentPage;

        // 比如设置了5条，如果总页数都只有四条，那么肯定都是全是显示哦

        if (pageNo+currentPage-1>=this.totalPage)

            this.pageNo = pageNo;

        else this.pageNo = this.totalPage-currentPage+1;

    }

    public List<T> getList() {

        return list;

    }

    public void setList(List<T> list) {

        this.list = list;

    }

    public Integer getTotalNum() {

        return totalNum;

    }

    public void setTotalNum(Integer totalNum) {

        this.totalNum = totalNum;

    }

    public Integer getTotalPage() {

        return totalPage;

    }

    public void setTotalPage(Integer totalPage) {

        this.totalPage = totalPage;

    }

    public Integer getCurrentPage() {

        return currentPage;

    }

    public void setCurrentPage(Integer currentPage) {

        this.currentPage = currentPage;

    }

    public Integer getPageSize() {

        return pageSize;

    }

    public void setPageSize(Integer pageSize) {

        this.pageSize = pageSize;

    }

    public Integer getStart() {

        return start;

    }

    public void setStart(Integer start) {

        this.start = start;

    }

    public Integer getPageNo() {

        return pageNo;

    }

    public void setPageNo(Integer pageNo) {

        this.pageNo = pageNo;

    }

}

package com.Dy.Pojo;

public class User {

    private Integer id;

    private String username;

    private String password;

    public Integer getId() {

        return id;

    }

    public void setId(Integer id) {

        this.id = id;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

}

3.构造Dao（可以使用逆向工程，这里为了展示就手打接口和xml了）

package com.Dy.Mapper;

import java.util.List;

import com.Dy.Pojo.User;

public interface UserMapper {

    public List<User> findAllUsers();

}

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE mapper

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!-- 这里的namespace是为了去绑定那个接口，让xml文件知道对应的是哪个接口 -->

<mapper namespace="com.Dy.Mapper.UserMapper">

    <!-- id于接口的名字一样 -->

    <select id="findAllUsers"  resultType="com.Dy.Pojo.User">

        select * from user

    </select>

</mapper>

4.构造Service

package com.Dy.Service;

import com.Dy.Pojo.PageInfo;

import com.Dy.Pojo.User;

public interface UserService {

    public PageInfo<User> findAllUsersByPage(Integer currentPage,Integer pageSize);

}

package com.Dy.Service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.Dy.Mapper.UserMapper;

import com.Dy.Pojo.PageInfo;

import com.Dy.Pojo.User;

@Service

public class UserServiceImpl implements UserService {

    @Autowired

    private UserMapper usermapper;

    @Override

    public PageInfo<User> findAllUsersByPage(Integer currentPage, Integer pageSize) {

        List<User> users = usermapper.findAllUsers();

        PageInfo<User> pageInfo = new PageInfo<>(users.size(), currentPage, pageSize, 5);

        //判断是否是最后一页,如果最后一页就显示最后一页的几条，不是最后一页就显示pageSize条

        if(currentPage==pageInfo.getTotalPage())

            pageInfo.setList(users.subList((currentPage-1)*pageSize, users.size()));

        else

            pageInfo.setList(users.subList((currentPage-1)*pageSize, (currentPage-1)*pageSize+pageSize));

        return pageInfo;

    }

}

5.JSP部分

　　　　　　　　　　　　　　　　<div class="am-fr">

                                    <ul class="am-pagination">

                                        <li ><a href="Users?currentPage=${page.currentPage-1 }">«</a></li>

                                        <c:forEach begin="${page.currentPage }"  end="${page.pageNo }" var="i">

                                        <li><a href="Users?currentPage=${i }">${i }</a></li>

                                        </c:forEach>

                                        <li><a href="#">»</a></li>

                                    </ul>

                                </div>

                            </div>

                                <tbody>

                                    <c:forEach items="${page.list }" var="page">

                                        <tr>

                                            <td><input type="checkbox" /></td>

                                            <td>${page.id }</td>

                                            <td>${page.username }</td>

                                            <td>${page.password }</td>

                                            <td>

                                                <div class="am-btn-toolbar">

                                                    <div class="am-btn-group am-btn-group-xs">

                                                        <button

                                                            class="am-btn am-btn-default am-btn-xs am-text-secondary">

                                                            <span class="am-icon-pencil-square-o"></span> 编辑

                                                        </button>

                                                        <button

                                                            class="am-btn am-btn-default am-btn-xs am-hide-sm-only">

                                                            <span class="am-icon-copy"></span> 复制

                                                        </button>

                                                        <button

                                                            class="am-btn am-btn-default am-btn-xs am-text-danger am-hide-sm-only">

                                                            <span class="am-icon-trash-o"></span> 删除

                                                        </button>

                                                    </div>

                                                </div>

                                            </td>

                                        </tr>

                                    </c:forEach>

                                </tbody>

                            </table>

6.页面展示

7.后期完善

　　1.分页逻辑没有考虑增加和删除不知道会不会有问题

　　2.PageInfo中的pageNo字段设计的很不合理，最后一页了就只显示一个，任需完善。

　　3.可以把Service分页逻辑再封装成一个方法，增加代码重用

巴特西