总结一下这几节Java课的...重点！！！

1.定义一个Person类，包含两个私有的属性（name、age）、一个含参的方法setValue(int age,String name)、一个不含参方法setValue()和一个普通方法tell()。

定义一个测试类Test，实例化一个Person类的对象，名为p；对两个属性赋值并输出结果。

 class Person
 {
     private int age;
     private String name;
     public void tell()
     {
         System.out.print("姓名："+name+"，年龄："+age);
     }
     public void setValue(int age,String name)
     {
         this.age=age;
         this.name=name;
     }
     public void setValue()
     {
         this.name="张三";
         this.age=21;
     }
 }
 public class Test
 {

     public static void main(String[] args)
     {
         Person p = new Person();
         p.setValue(21,"Mary");
         p.tell();
     }
 }

2.定义一个Student类，继承自Person类，含有一个protected访问权限的字符型属性sex，定义Student类的构造方法，并覆写父类的tell()方法，实现对三个属性的赋值和输出。

 class Person
 {
     private int age;
     private String name;
     public void tell()
     {
         System.out.print("姓名："+name+"，年龄："+age);
     }
     public void setValue(int age,String name)
     {
         this.age=age;
         this.name=name;
     }
     public void setValue()
     {
         this.name="张三";
         this.age=21;
     }
 }
 class Student extends Person
 {
     protected char sex;
     Student(int age,String name,char sex)
     {
         super.setValue(age,name);
         this.sex=sex;
     }
     public void tell()
     {
         super.tell();
         System.out.println("，性别："+sex);
     }
 }
 public class Test
 {

     public static void main(String[] args)
     {
         Student s = new Student(20,"Mary",'女');
         s.tell();
     }
 }

3.数据库访问的实现

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

 public class MySQL
 {
     public static void main(String[] args){
         Connection conn = null;
         Statement stmt = null;
         ResultSet rs =null;
         try
         {
             Class.forName("com.mysql.jdbc.Driver");
             conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/studentInfo","root","123456");
             stmt = conn.createStatement();
             rs = stmt.executeQuery("select * from student");
             while(rs.next())
             {
                 String no = rs.getString(1);
                 String name = rs.getString("sName");
                 String sex = rs.getString(3);
                 int age = rs.getInt(4);
                 String dept = rs.getString("dept");
                 System.out.println(no+"__"+name+"__"+sex+"  "+age+"  "+dept+"__");
             }
         }
         catch(Exception e)
         {
             e.printStackTrace();
         }
         finally
         {
             try
             {
                 if(rs !=null) rs.close();
                 if(stmt!=null) stmt.close();
                 if(conn !=null) conn.close();
              }
             catch(SQLException e)
             {
                 e.printStackTrace();
             }
         }
     }
 }

这是重点！这是重点！这是重点！重要的事情说三遍！！！