SQL前后端分页

package com.neusoft.bean;

import java.util.List;

public class Page<T> {
	private List<T> data;   //后台数据库查询出来
	private int totalRecord; //表示总共有多少记录，从数据库中查询出来
	
//	private int totalPage;  // 表示总共有多少页，计算得到！
//	private int index;   //表示当前索引值，计算出来的！
	
	private int pageNumber; //表示的是当前页码，这个参数是从页面传递过来的！
	private int pageSize;  //表示的是每页显示多少条数据 ，在servlet中设置的！
	private String path;
	
	
	public Page() {
		super();
	}
	
	public Page(int totalRecord, int pageNumber, int pageSize) {
		super();
		this.totalRecord = totalRecord;
		this.pageNumber = pageNumber;
		this.pageSize = pageSize;
	}


	
	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public List<T> getData() {
		return data;
	}

	public void setData(List<T> data) {
		this.data = data;
	}

	public int getTotalRecord() {
		return totalRecord;
	}

	public void setTotalRecord(int totalRecord) {
		this.totalRecord = totalRecord;
	}

	public int getTotalPage() {
		/**
		 * totalPage:表示总共有几页！
		 * 
		 *					 总页数          totalRecord[总记录数]    pageSize
		 *                     5        10                     2
		 *                     5         9                     2
		 *                     4         8                     2
		 */
		if(totalRecord % pageSize ==0){
			return totalRecord / pageSize;
		}
		
		return (totalRecord / pageSize + 1);
	}

	public int getIndex() {
		/**
		 * index表示的是当前索引值，是计算得到的！
		 *             当前索引值           每页显示几条数据               当前页是第几页
		 *                0           3                 1
		 *                3           3                 2
		 *        
				index  = (pageNumber -1)*pageSize;
		 */
		return (getPageNumber() -1)*pageSize;
	}

	
	public int getPageNumber() {
		if(pageNumber < 1){
			return 1;
		}else if(pageNumber > getTotalPage()){
			return getTotalPage();
		}
		return pageNumber;
	}

	
	public int getPageSize() {
		return pageSize;
	}

	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

}

package com.neusoft.bean;

public class Student {
	private  int id;
	private  String name;
	private  String school;
	private  String score;
	public Student() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Student(int id, String name, String school, String score) {
		super();
		this.id = id;
		this.name = name;
		this.school = school;
		this.score = score;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getSchool() {
		return school;
	}
	public void setSchool(String school) {
		this.school = school;
	}
	public String getScore() {
		return score;
	}
	public void setScore(String score) {
		this.score = score;
	}
	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", school=" + school + ", score=" + score + "]";
	}
	
}

package com.neusoft.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.neusoft.bean.Student;
import com.neusoft.utils.JDBCUtil;

public class StudentDao {
	 public List<Student> getStudentList(){    	  	
    	 PreparedStatement ps=null;
    	 ResultSet rs =null;
    	 List<Student> list=new ArrayList<Student>();
    	 Connection conn=JDBCUtil.getConnection();
    	 String sql="select * from student";
    	 try {
    		  ps = conn.prepareStatement(sql);
              
              rs = ps.executeQuery();
			while (rs.next()) {
				Student stu=new Student();
				int id = rs.getInt("id");
				String username = rs.getString("name");
				String school = rs.getString("school");
				String score = rs.getString("score");
				stu.setId(id);
				stu.setName(username);
				stu.setSchool(school);
				stu.setScore(score);
				list.add(stu);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {			
			JDBCUtil.close(ps, rs, conn);
		}
		return list;
    	 
     }
	   public static int delete(int id){
			return JDBCUtil.executeUpdate("delete from student where id=?",id);
			
		}
		public int update(Student student){
			return JDBCUtil.executeUpdate("update student set name=?,school=?,score=? where id=?",student.getName(),student.getSchool(),student.getScore(),student.getId());
		}
		
		public int add(Student student){
			return JDBCUtil.executeUpdate("insert into student (id,name,school,score) values (?,?,?,?)",null,student.getName(),student.getSchool(),student.getScore());
		}
		 public List<Student> getStudent(Student student){    	  	
	    	 PreparedStatement ps=null;
	    	 ResultSet rs =null;
	    	 List<Student> list=new ArrayList<Student>();
	    	 Connection conn=JDBCUtil.getConnection();
	    	 String sql="select * from student where  name= ‘"+student.getName()+"‘";
	    	 try {
	    		  ps = conn.prepareStatement(sql);	              
	              rs = ps.executeQuery();
				while (rs.next()) {
					Student stu=new Student();
					int id = rs.getInt("id");
					String username = rs.getString("name");
					String school = rs.getString("school");
					String score = rs.getString("score");
					stu.setId(id);
					stu.setName(username);
					stu.setSchool(school);
					stu.setScore(score);
					list.add(stu);
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}finally {			
				JDBCUtil.close(ps, rs, conn);
			}
			return list;
	    	 
	     }
		public Student getStuInfoById(String id) {
			 PreparedStatement ps=null;
	    	 ResultSet rs =null;
			 Student stu=null;
	    	 List<Student> list=new ArrayList<Student>();
	    	 Connection conn=JDBCUtil.getConnection();
	    	 String sql="select * from student where id = ?";
	    	 try {
	    		  ps = conn.prepareStatement(sql);
	              ps.setInt(1, Integer.parseInt(id));
	              rs = ps.executeQuery();
				while (rs.next()) {	
					stu=new Student();
					String username = rs.getString("name");
					String school = rs.getString("school");
					String score = rs.getString("score");
					stu.setId(Integer.parseInt(id));
					stu.setName(username);
					stu.setSchool(school);
					stu.setScore(score);
					list.add(stu);
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}finally {			
				JDBCUtil.close(ps, rs, conn);
			}
			return stu;
		}
		public int getTotalRecord() {
			PreparedStatement ps=null;
	    	 ResultSet rs =null;
	    	 Connection conn=JDBCUtil.getConnection();
	    	 String sql="select count(*) as total from student ";
	    	 int total=0;
	    	 try {
	    		  ps = conn.prepareStatement(sql);
	              rs = ps.executeQuery();
				while (rs.next()) {	
					total= rs.getInt("total");
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}finally {			
				JDBCUtil.close(ps, rs, conn);
			}
			return total;
		}
		public List<Student> getLimitStuList(int index, int pageSize) {
			PreparedStatement ps=null;
	    	 ResultSet rs =null;
	    	 Connection conn=JDBCUtil.getConnection();
	    	 String sql="select *  from student limit ? , ?";
	    	 List<Student> list= new ArrayList<Student>();
	    	 try {
	    		  ps = conn.prepareStatement(sql);
	    		  ps.setInt(1, index);
	    		  ps.setInt(2, pageSize);
	              rs = ps.executeQuery();
				while (rs.next()) {	
					int id=rs.getInt("id");
					String name = rs.getString("name");
					String school = rs.getString("school");
					String score = rs.getString("score");
					list.add(new Student(id,name,school,score));
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}finally {			
				JDBCUtil.close(ps, rs, conn);
			}
			return list;
		}
}

package com.neusoft.service;

import java.util.List;

import com.neusoft.bean.Page;
import com.neusoft.bean.Student;
import com.neusoft.dao.StudentDao;

public class StudentService {
    private StudentDao stuDao=new StudentDao();
    public Page<Student> getStudentList(int pageNo, int pageSize){
    	//第一步：查询当前表的所有记录数
    			int totalRecord=  stuDao.getTotalRecord();
    			//第二步：创建page对象
    			Page<Student> page = new Page<Student>(totalRecord,pageNo,pageSize);
    			//第三步：查询分页列表数据并设置到page对象中！
    			List<Student> list = stuDao.getLimitStuList(page.getIndex(),page.getPageSize());
    			page.setData(list);
    		
    			return page;
    }
    public List<Student> getStudent(Student student){
    	return stuDao.getStudent(student);
    }
	public Student getStuInfoById(String id) {
		// TODO Auto-generated method stub
		return stuDao.getStuInfoById(id);
	}
	public int Add(Student student){
		return stuDao.add(student);
	}
	public int Update(Student student){
		return stuDao.update(student);
	}
}

package com.neusoft.servlet;


import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class BaseServlet
 */
@WebServlet("/BaseServlet")
public class BaseServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	protected static int pageSize=1;
	protected static int pageNo=1;
       

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		request.setCharacterEncoding("utf8");
		try {
			pageNo =Integer.parseInt(request.getParameter("pageNo"));
		} catch (Exception e) {
			e.getMessage();
		}
		
		//获取用户传递的请求参数
		String methodName = request.getParameter("method");
		//通过方法名获取到方法的对象
		//获取当前类的Class对象
		Class<? extends BaseServlet> cla = this.getClass();
		//获取cla的的方法（Method对象）
		//getDeclaredMethod需要两个参数，方法名和参数名
		//因为在java需要通过方法名和参数列表来确定一个方法
		try {
			//获取方法对象
			Method method = cla.getDeclaredMethod(methodName, HttpServletRequest.class , HttpServletResponse.class);
			//设置方法的访问权限
			method.setAccessible(true);
			//调用方法
			//invoke用于调用一个方法，第一个参数时要调用方法的对象，剩下是调用方法需要的参数
			method.invoke(this, request , response);
		}catch (InvocationTargetException e) {
			System.out.println("此处接收被调用方法内部未被捕获的异常");
			e.getMessage();
	    }catch (Exception e) {
			e.printStackTrace();
		}
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		request.setCharacterEncoding("utf8");
		doGet(request, response);
		
	}

}

package com.neusoft.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.neusoft.bean.Page;
import com.neusoft.bean.Student;
import com.neusoft.dao.StudentDao;
import com.neusoft.service.StudentService;
import com.neusoft.utils.WEBUtils;



@WebServlet("/StudentServlet")
public class StudentServlet extends BaseServlet {
	private static final long serialVersionUID = 1L;
	private StudentService stuService=new StudentService();
	
	protected void getStuList(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		String url = WEBUtils.getPath(request);
		Page<Student> page = stuService.getStudentList(pageNo,pageSize);
		page.setPath(url);
		request.setAttribute("page",page);
		request.getRequestDispatcher("/WEB-INF/view/main.jsp").forward(request, response);
	}
	protected void toUpdatePage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		String id = request.getParameter("id");
		Student stu= stuService.getStuInfoById(id);
		if (stu != null) {
			request.setAttribute("stu",stu);
			request.getRequestDispatcher("/WEB-INF/view/update.jsp").forward(request, response);
		}
		
	}
	protected void Delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		String ids = request.getParameter("id");
		int id=Integer.parseInt(ids);
		StudentDao.delete(id);
		getStuList(request, response);
		//request.getRequestDispatcher("/WEB-INF/view/main.jsp").forward(request, response);
	}
	protected void Update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		request.setCharacterEncoding("utf8");
		String name = request.getParameter("name");
		String school = request.getParameter("school");
		String score = request.getParameter("score");
		int id=Integer.parseInt(request.getParameter("id"));
		Student student=new Student();
		student.setName(name);
		student.setSchool(school);
		student.setScore(score);
		student.setId(id);
		System.out.println(name);
		stuService.Update(student);		
//			response.sendRedirect("/Regist-success.html");//重定向
		getStuList(request, response);
		
	}
	protected void Add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {	
		request.setCharacterEncoding("utf8");	
		String name = request.getParameter("name");
		String school = request.getParameter("school");
		String score = request.getParameter("score");
		Student student=new Student();
		student.setName(name);
		student.setSchool(school);
		student.setScore(score);
		List<Student> student2 = stuService.getStudent(student);
		System.out.println(student2.toString());
		if (student2.isEmpty()) {
			stuService.Add(student);
			getStuList(request, response);
			
		}else  {
//			response.sendRedirect("/Regist-success.html");//重定向
			request.getRequestDispatcher("/WEB-INF/view/insert-error.jsp").forward(request, response);//转发
		}
	}

}

package com.neusoft.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class TOInsert
 */
@WebServlet("/TOInsert")
public class TOInsert extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
  
	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.getRequestDispatcher("/WEB-INF/view/insert.jsp").forward(request, response);
	
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
		request.setCharacterEncoding("utf8");
	}

}

package com.neusoft.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCUtil {
	private static String driver="com.mysql.jdbc.Driver";
	private static String url="jdbc:mysql://localhost:3306/demo";
	private static String username="root";
	private static String password="123456";
	static{
		
		try {//加载驱动
			Class.forName(driver);			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	public static Connection getConnection(){//创建连接
			try {
				return DriverManager.getConnection(url, username, password);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				return null;
			}
		}
	
	public static void close(Statement st,ResultSet rs,Connection conn){//全部关闭
		if (conn !=null) {
			 try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (rs !=null) {
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (st !=null) {
			try {
				st.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	public static void close(Connection conn){
		try {
			conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	public static void close(PreparedStatement ps){
		try {
			ps.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	public static void close(ResultSet rs){
		try {
			rs.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	
	//封装函数，直接传参使用
	public static int executeUpdate(String sql,Object... papram) {
		// TODO Auto-generated method stub
		Connection conn =getConnection();
		int result=0;
		try {
			PreparedStatement pst = conn.prepareStatement(sql);
			if (papram!=null) {
				for (int i = 0; i < papram.length; i++) {
					pst.setObject(i+1, papram[i]);
				}
			}
			result =pst.executeUpdate();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			close(conn);
		}
		return result;

	}
}

package com.neusoft.utils;

import javax.servlet.http.HttpServletRequest;

public class WEBUtils {
	public static String getPath(HttpServletRequest request){
		String requestURI = request.getRequestURI();
		String queryString = request.getQueryString();
		String url = requestURI+"?"+queryString;
		if(url.contains("&pageNo")){
			url = url.substring(0, url.indexOf("&pageNo"));
		}
		if(url.contains("Update")){
			url = url.replace("Update", "getStuList");
		}
		if(url.contains("Add")){
			url = url.replace("Add", "getStuList");
		}
		if(url.contains("Delete")){
			url = url.replace("Delete", "getStuList");
		}
		return url;
	}
}