对学生表的增删改查操作

      大三暑假在实习，第二周已经结束了，现在可以自己动手写一些比较小的工程。就是写出来调试真的好费人。

简单介绍一下，有一个简单的学生信息表，数据库设计如下：

然后，根据MVC进行分层处理：

    

程序运行结果：

1、查询数据库的结果。

2、点击新增

3、点击编辑，会获取到Id，进行对应的编辑

4、点击删除，直接删除。

package com.mm.bean;

public class Student {
	int id;//学号
	String name;//姓名
	int age;//年龄
	String classes;//班级
	
	public Student(){}

	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 int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getClasses() {
		return classes;
	}

	public void setClasses(String classes) {
		this.classes = classes;
	}
	
}

package com.mm.Dao;

import java.util.List;

import com.mm.bean.Student;

public interface IStuDao {
	/**
	 * 新增一个学生
	 * @param stu
	 */
	public void addstu(Student stu);
	/**
	 * 修改一个学生
	 * @param stu
	 */
	public void updatestu(Student stu);
	/**
	 * 通过ID删除一个学生
	 * @param id
	 */
	public void delstu(int id);
	/**
	 * 找到所有的学生
	 * @return 返回一个集合
	 */
	public List<Student> findall();
	/**
	 * 通过id找到一个学生
	 * @param id
	 * @return
	 */
	public Student findStubyId(int id);

}

package com.mm.Dao.impl;

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.mm.Dao.IStuDao;
import com.mm.bean.Student;
import com.mm.db.JDBCUtils;

public class StuDaoImpl implements IStuDao {

    public void addstu(Student stu) {
        // TODO Auto-generated method stub
        String s1 = "INSERT INTO student (id,name,age,class) VALUES(?,?,?,?)";
        try {
            Connection con = JDBCUtils.getconnection();
            PreparedStatement prep = con.prepareStatement(s1);
            prep.setInt(1, stu.getId());
            prep.setString(2, stu.getName());
            prep.setInt(3, stu.getAge());
            prep.setString(4, stu.getClasses());
            prep.executeUpdate();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{

            JDBCUtils.release();
                 }

} 
public void updatestu(Student stu) {
          String s1 = "update student set name=?,age=?,class=? where id=?"; 
          try {
             Connection con = JDBCUtils.getconnection(); 
             PreparedStatement prep = con.prepareStatement(s1);
             prep.setInt(4, stu.getId()); //第4个问号的值
             prep.setString(1, stu.getName()); 
             prep.setInt(2, stu.getAge()); 
             prep.setString(3, stu.getClasses()); 
             prep.executeUpdate(); 
             } catch (SQLException e) { 
                 e.printStackTrace();
             }finally{

              JDBCUtils.release();
          }

} 


public void delstu(int id){ 
      String s5 = "delete from student where id =?" ; 
      Connection con = null; 
      try { 
         con = JDBCUtils.getconnection(); 
         PreparedStatement prep = con.prepareStatement(s5);
         prep.setInt(1,id); 
         prep.executeUpdate(); 
        } catch (SQLException e) { 
          e.printStackTrace();
        }finally{

           JDBCUtils.release();
                 }
        
        

    }

    public List<Student> findall() {
        
        String s2 = "select * from student";
        Connection con = null;
        List<Student> list = new ArrayList();
        try {
            con = com.mm.db.JDBCUtils.getconnection();
            PreparedStatement ps = con.prepareStatement(s2);
            ResultSet rs = ps.executeQuery();

            while (rs.next()) {
                list.add(toStu(rs));
            }
        } catch (SQLException e) {
        
            e.printStackTrace();
        }finally{

                   JDBCUtils.release();
                 }

         return list; 
         }
    
    
//将一行数据封装成一个对象
 private Student toStu(ResultSet rs) throws SQLException { 
        Student s = new Student(); 
        s.setId(rs.getInt("id")); 
        s.setName(rs.getString("name")); 
        s.setAge(rs.getInt("age")); 
        s.setClasses(rs.getString("class")); 
        return s; 
     } 
public Student findStubyId(int id) {
     String s3 = "select * from student where id =" + id;
     Connection con = null; 
     PreparedStatement ps = null;
     ResultSet rs = null; 
     List<Student> li = new ArrayList();
    try { 
    con = com.mm.db.JDBCUtils.getconnection(); 
    ps = con.prepareStatement(s3); 
    rs = ps.executeQuery();
     while (rs.next()) {
         return toStu(rs); 
    }  } catch (SQLException e) { // TODO Auto-generated catch block
       e.printStackTrace(); 
    }finally{
      JDBCUtils.release();
      }
       return null;
}

　

package com.mm.db;

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 JDBCUtils {

    /**
     * @param args
     * @throws SQLException
     */
    public static Connection getconnection() throws SQLException {

        try {
            Class.forName("com.mysql.jdbc.Driver");
            return DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/test", "mxning", "mxning");

        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
    public static void release(ResultSet rs,PreparedStatement ps,Connection con){
        
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if(ps!=null){
            try {
                ps.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
        if(con!=null){
            try {
                con.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
}

　

package com.mm.sevlet;

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

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

import com.mm.Dao.IStuDao;
import com.mm.Dao.impl.StuDaoImpl;
import com.mm.bean.Student;

public class studentServlet extends HttpServlet {

	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
        IStuDao sd = new StuDaoImpl();
        String op = request.getParameter("op");
        if(op==null)    op = "list";
        if("list".equals(op)){
        	//接收 显示所有的请求信息
        	List<Student> list = sd.findall();
        	request.setAttribute("list", list);
        	response.sendRedirect("studentlist.jsp");
        	return ;
        }else if("add".equals(op)){
        	//若是新增,则跳转到新增界面处理
        	response.sendRedirect("studentadd.jsp");
        	return ;
        }else if("edit".equals(op)){
        	//取到要编辑的数据，然后 若command=view 则转向view.jsp;否则跳转到编辑页面
        	String id = request.getParameter("id");
        	//System.out.println(id);
        	Student s = sd.findStubyId(Integer.parseInt(id));
        	request.setAttribute("stu", s);
        	String command = request.getParameter("command");
        	if("view".equals(command)){
        		request.getRequestDispatcher("studentedit.jsp").forward(request, response);
        		//response.sendRedirect("studentedit.jsp");
        		return ;
        	}else{
        		response.sendRedirect("studentview.jsp?id="+id);
        		return ;
        	}
        	
        	
        }else if("delete".equals(op)){
        	//删除数据，然后跳转到列表页面
			//1.获取参数值
			String id =request.getParameter("id");
			
			//2.调用dao删除指定的数据
			sd.delstu(Integer.parseInt(id));
			
			//3.通过response返回到列表页面
			response.sendRedirect("studentServlet?op=list");
			
			return ;
        }else if("store".equals(op)){
			//若是新增，则add；若是编辑，则调用update;然后跳转到列表页面
			//1.获取参数值
			String id =request.getParameter("id");
			String name = request.getParameter("name");
			String age = request.getParameter("age");
			String classes = request.getParameter("class");
			System.out.println(id+name+age);
			System.out.println(classes+"sssssssssssssss");
			//2.封装成对象
			Student obj =new Student();

			obj.setName(name);
			obj.setAge(Integer.parseInt(age));
			obj.setClasses(classes);	
			
			if(id==null||"".equals(id)){
				//新增
				sd.addstu(obj);		
				//System.out.println("sssssssssssssssssss");
				
			}else{
				//编辑
				obj.setId(Integer.parseInt(id));
				sd.updatestu(obj);				
			}
			response.sendRedirect("studentServlet?op=list");
			return ;
		}		
	}

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

}

<%@ page language="java"
	import="java.util.*,com.mm.Dao.*,com.mm.Dao.impl.*,com.mm.bean.*"
	pageEncoding="UTF-8"%>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://"
			+ request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
  request.setCharacterEncoding("utf-8");
  response.setCharacterEncoding("utf-8");
	IStuDao is = new StuDaoImpl();
	List<Student> list = is.findall();
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>学生列表显示界面</title>
</head>
<body>
	<table align="center" border="1" cellspacing="0">
		<tr>
			<td colspan="5"><button
					onclick="javascript:document.location.href='studentServlet?op=add';">新增</button>
			</td>
		</tr>
		<tr>
			<th>学号</th>
			<th>姓名</th>
			<th>年龄</th>
			<th>班级</th>
			<th>操作</th>
		</tr>
		<%
			int i = 1;
			for (Student st : list) {
		%>
		<tr>
			<td><%=i%></td>
			<td>
			<a href="studentview.jsp?op=edit&id=<%=st.getId()%>"><%=st.getName()%></a>
			</td>
			<td><%=st.getAge()%></td>
			<td><%=st.getClasses()%></td>
			<td><a href="studentServlet?op=edit&command=view&id=<%=st.getId()%>">编辑</a>  
			<a href="studentServlet?op=delete&id=<%=st.getId()%>">删除</a>
			</td>
		</tr>
		<%
			i++;
			}
		%>
	</table>
</body>
</html>

<%@ page language="java" import="java.util.*,com.mm.Dao.*,com.mm.Dao.impl.*,com.mm.bean.*" pageEncoding="UTF-8"%>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://"
			+ request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
			
	String id = request.getParameter("id");		
	IStuDao is = new StuDaoImpl();
	Student s = is.findStubyId(Integer.parseInt(id));
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>每个学生查看界面</title>
</head>

<body>
	<h3 align="center">学生查看</h3>
	
	<table align="center" width="60%" border="1" cellspacing="0">
	    <tr><td colspan="2"><button onclick="javascript:history.back(-1);">返回</button></td></tr>
		
		<tr>
			<td>姓名</td>
			<td><%=s.getName()%></td>
		</tr>
		<tr>
			<td>年龄</td>
			<td><%=s.getAge()%></td>
		</tr>
		<tr>
			<td>班级</td>
			<td><%=s.getClasses() %></td>
		</tr>
	</table>
</body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'studentadd.jsp' starting page</title>

  </head>
  
  <body>
  
    <form action="studentServlet?1=1&op=store" method="post">
       <table border = "1" cellspacing = "0" align = "center">
         <tr>
				<th colspan="2" align="left"><button type="submit">提交</button></button>
				</th>
		</tr>
		
		<tr><td>姓名</td><td><input type = "text"  name = "name" /></td></tr>
		<tr><td>年龄</td><td><input type = "text"  name = "age" /></td></tr>
		<tr><td>班级</td><td><input type = "text"  name = "class" /></td></tr>
       
       </table>    
    </form>
    
    
  </body>
</html>

<%@ page language="java" import="java.util.*,com.mm.bean.*,com.mm.sevlet.*"
	pageEncoding="UTF-8"%>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://"
			+ request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>修改学生界面</title>

</head>

<body>
	<%
		Student s = (Student) request.getAttribute("stu");
	%>
	<form action="studentServlet?op=store"  method = "post">
		<input type="hidden" name="id" value="<%=s.getId()%>" />

		<table border="1" align="center" cellspacing="0">
			<tr>
				<td colspan="2"><button type="submit">提交</button>  				
					<button type="button" onclick="javascript:history.back(-1);">返回</button>
				</td>
			</tr>
			
			<tr>
				<td>姓名</td>
				<td><input type="text" name="name" value="<%=s.getName()%>" />
				</td>
			</tr>
			<tr>
				<td>年龄</td>
				<td><input type="text" name="age" value="<%=s.getAge()%>" />
				</td>
			</tr>
			<tr>
				<td>班级</td>
				<td><input type="text" name="class" value="<%=s.getClasses()%>" />
				</td>
			</tr>
		</table>

	</form>

</body>
</html>