采用MVC模式JDBC演示案例

MVC三层架构：

Model 模型层，数据处理和业务逻辑

View 视图层，为客户展示内容

Control 控制层，协调控制，更新模型

案例如下：

1、获得数据库连接

 package com.db;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;

 public class JDBCUtil {

     private static final String URL="jdbc:mysql://127.0.0.1:3306/student";
     private static final String USER="root";
     private static final String PASSWORD="root";
     private static Connection conn = null;

     static{
         try {
             Class.forName("com.mysql.jdbc.Driver");
             conn = DriverManager.getConnection(URL, USER, PASSWORD);
         } catch (ClassNotFoundException e) {
             e.printStackTrace();
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }

     public static Connection getConn(){
         return conn;
     }

 }

2、创建模型

 package com.model;

 public class Student {

     private int id;
     private String name;
     private char sex;
     private int age;
     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 char getSex() {
         return sex;
     }
     public void setSex(char sex) {
         this.sex = sex;
     }
     public int getAge() {
         return age;
     }
     public void setAge(int age) {
         this.age = age;
     }

 }

3、创建数据库访问对象--DAO

 package com.dao;

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

 import com.zhidi.db.JDBCUtil;
 import com.zhidi.model.Student;

 public class StuUtile {

     private static final Connection conn = JDBCUtil.getConn();

     //添加
     public void addStu(Student stu) throws SQLException{
         String sql = "insert into stu"+
                     "(id,name,sex,age) values (?,?,?,?)";
         PreparedStatement ps = conn.prepareStatement(sql);
         ps.setInt(1, stu.getId());
         ps.setString(2, stu.getName());
         ps.setString(3,String.valueOf(stu.getSex()));
         ps.setInt(4, stu.getAge());

         ps.execute();

     }

     //删除
     public void delStu(int id) throws SQLException{
         String sql = "delete from stu where id=?";
     PreparedStatement ps = conn.prepareStatement(sql);
     ps.setInt(1,id);

     ps.execute();
     }

     //修改
     public void updateStu(Student stu) throws SQLException{
         String sql = "update stu set name=?,sex=?,age=? where "+
                 "id=?";
     PreparedStatement ps = conn.prepareStatement(sql);
     ps.setString(1, stu.getName());
     ps.setString(2,String.valueOf(stu.getSex()));
     ps.setInt(3, stu.getAge());
     ps.setInt(4, stu.getId());

     ps.execute();
     }

     //查询所有学生
     public List<Student> query() {
         List<Student> list = new ArrayList<Student>();
         try {
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery("select * from stu");

             Student stu = null;
             while(rs.next()){
                 stu = new Student();
                 stu.setId(rs.getInt("id"));
                 stu.setName(rs.getString("name"));
                 String sex = rs.getString("sex");
                 char[] ch = sex.toCharArray();
                 for (char c : ch) {
                     stu.setSex(c);
                 }
                 stu.setAge(rs.getInt("age"));
                 list.add(stu);
             }

         } catch (SQLException e) {
             e.printStackTrace();
         }

         return list;
     }

     //查询单个学生
     public Student getStu(int id) throws SQLException{
         String sql = "select * from stu where id=?";
     PreparedStatement ps = conn.prepareStatement(sql);
     ps.setInt(1, id);

     ResultSet rs = ps.executeQuery();
     Student stu = null;
     while(rs.next()){
         stu = new Student();
         stu.setId(rs.getInt("id"));
         stu.setName(rs.getString("name"));
         String sex = rs.getString("sex");
         char[] ch = sex.toCharArray();
         for (char c : ch) {
             stu.setSex(c);
         }
         stu.setAge(rs.getInt("age"));
     }
         return stu;
     }

 }

4、控制层逻辑代码

 package com.control;

 import java.sql.SQLException;
 import java.util.List;

 import com.zhidi.dao.StuUtile;
 import com.zhidi.model.Student;

 public class StuControl {

     public static void main(String[] args) throws SQLException {
         StuUtile su = new StuUtile();
         Student stu = new Student();
         stu.setId(10);
         stu.setName("张芳");
         stu.setSex('女');
         stu.setAge(20);
 //        su.addStu(stu);

 //        su.updateStu(stu);

 //        su.delStu(10);
         Student s = su.getStu(1);
         System.out.println(s.getId()+" "+s.getName()+" "+s.getSex()+" "+s.getAge());

 //        List<Student> list = su.query();
 //        for (Student s : list) {
 //            System.out.println(s.getId()+" "+s.getName()+" "+s.getSex()+" "+s.getAge());
 //        }

     }

 }