Java案例怎么实现分页分页算法？

wen java案例 2026-06-09 8

Java分页算法实现案例

我为你提供几种常见的Java分页实现方案：

Java案例怎么实现分页分页算法？

基础内存分页（手动实现）

import java.util.ArrayList;
import java.util.List;
public class PaginationUtil {
    /**
     * 手动内存分页
     * @param dataList 原始数据列表
     * @param pageNum 当前页码（从1开始）
     * @param pageSize 每页大小
     * @return 当前页的数据
     */
    public static <T> List<T> paginate(List<T> dataList, int pageNum, int pageSize) {
        if (dataList == null || dataList.isEmpty()) {
            return new ArrayList<>();
        }
        int totalCount = dataList.size();
        int startIndex = (pageNum - 1) * pageSize;
        int endIndex = Math.min(startIndex + pageSize, totalCount);
        if (startIndex >= totalCount) {
            return new ArrayList<>();
        }
        return dataList.subList(startIndex, endIndex);
    }
    /**
     * 计算总页数
     */
    public static int getTotalPages(int totalCount, int pageSize) {
        return (int) Math.ceil((double) totalCount / pageSize);
    }
}

完整的分页结果对象

import java.util.List;
public class PageResult<T> {
    private List<T> data;          // 当前页数据
    private int pageNum;           // 当前页码
    private int pageSize;          // 每页大小
    private long totalCount;       // 总记录数
    private int totalPages;        // 总页数
    private boolean hasPrevious;   // 是否有上一页
    private boolean hasNext;       // 是否有下一页
    public PageResult(List<T> data, long totalCount, int pageNum, int pageSize) {
        this.data = data;
        this.totalCount = totalCount;
        this.pageNum = pageNum;
        this.pageSize = pageSize;
        this.totalPages = (int) Math.ceil((double) totalCount / pageSize);
        this.hasPrevious = pageNum > 1;
        this.hasNext = pageNum < totalPages;
    }
    // Getters and Setters
    public List<T> getData() { return data; }
    public int getPageNum() { return pageNum; }
    public int getPageSize() { return pageSize; }
    public long getTotalCount() { return totalCount; }
    public int getTotalPages() { return totalPages; }
    public boolean isHasPrevious() { return hasPrevious; }
    public boolean isHasNext() { return hasNext; }
}

使用Stream API实现分页

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
public class StreamPagination {
    public static <T> PageResult<T> paginateWithStream(List<T> dataList, int pageNum, int pageSize) {
        long totalCount = dataList.size();
        List<T> pageData = dataList.stream()
            .skip((pageNum - 1) * pageSize)
            .limit(pageSize)
            .collect(Collectors.toList());
        return new PageResult<>(pageData, totalCount, pageNum, pageSize);
    }
}

数据库SQL分页（以MySQL为例）

import java.sql.*;
public class DatabasePagination {
    /**
     * 执行分页查询
     */
    public PageResult<User> queryUsersByPage(int pageNum, int pageSize) {
        String countSql = "SELECT COUNT(*) FROM users";
        String querySql = "SELECT * FROM users LIMIT ?, ?";
        int offset = (pageNum - 1) * pageSize;
        List<User> userList = new ArrayList<>();
        long totalCount = 0;
        try (Connection conn = getConnection();
             PreparedStatement countStmt = conn.prepareStatement(countSql);
             PreparedStatement queryStmt = conn.prepareStatement(querySql)) {
            // 获取总记录数
            ResultSet countRs = countStmt.executeQuery();
            if (countRs.next()) {
                totalCount = countRs.getLong(1);
            }
            // 查询当前页数据
            queryStmt.setInt(1, offset);
            queryStmt.setInt(2, pageSize);
            ResultSet rs = queryStmt.executeQuery();
            while (rs.next()) {
                User user = new User();
                user.setId(rs.getLong("id"));
                user.setName(rs.getString("name"));
                user.setEmail(rs.getString("email"));
                userList.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return new PageResult<>(userList, totalCount, pageNum, pageSize);
    }
    private Connection getConnection() throws SQLException {
        // 获取数据库连接（示例代码，实际需要配置）
        return DriverManager.getConnection("jdbc:mysql://localhost:3306/db", "user", "password");
    }
}

MyBatis-Plus 分页（简化版）

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;
    public PageResult<User> getUsersByPage(int pageNum, int pageSize) {
        // 创建分页对象
        Page<User> page = new Page<>(pageNum, pageSize);
        // 执行分页查询
        IPage<User> userPage = userMapper.selectPage(page, null);
        // 转换为自定义分页结果
        return new PageResult<>(
            userPage.getRecords(),
            userPage.getTotal(),
            pageNum,
            pageSize
        );
    }
}

使用示例

public class PaginationExample {
    public static void main(String[] args) {
        // 模拟数据
        List<String> data = new ArrayList<>();
        for (int i = 1; i <= 100; i++) {
            data.add("Item " + i);
        }
        // 手动分页
        List<String> pageData = PaginationUtil.paginate(data, 1, 10);
        System.out.println("第1页数据: " + pageData);
        // Stream分页
        PageResult<String> result = StreamPagination.paginateWithStream(data, 2, 10);
        System.out.println("总记录数: " + result.getTotalCount());
        System.out.println("总页数: " + result.getTotalPages());
        System.out.println("当前页数据: " + result.getData());
        System.out.println("是否有下一页: " + result.isHasNext());
    }
}

常见分页参数校验

public class PaginationValidator {
    public static void validate(int pageNum, int pageSize) {
        if (pageNum < 1) {
            throw new IllegalArgumentException("页码必须大于0");
        }
        if (pageSize < 1) {
            throw new IllegalArgumentException("每页大小必须大于0");
        }
        // 限制最大页容量，防止内存溢出
        int maxPageSize = 1000;
        if (pageSize > maxPageSize) {
            throw new IllegalArgumentException("每页大小不能超过" + maxPageSize);
        }
    }
}