java如何连接到数据库以及如何在数据库中插入变量

 1   //1. 注册驱动(告诉java驱动的实现类)
 2         Class.forName("com.mysql.jdbc.Driver");
 3         //2. 获取数据库的连接对象
 4         Connection conn = DriverManager.getConnection(
 5                 "jdbc:mysql://localhost:3306/hnkj",
 6                 "root",
 7                 "root");
 8         //3. 定义SQL语句，符合SQL规范
 9         String sql = "insert into dept2(dname,location)values(‘内勤部‘,‘洛阳‘)";
10         sql ="delete from dept2 where id=4";
11         //4. 获取执行SQL语句的对象
12         Statement stem = conn.createStatement();
13         //5. 执行SQL语句并处理结果(返回的受影响行数)
14         int num = stem.executeUpdate(sql);
15         //6. 处理返回结果
16         System.out.println(num>0?"成功":"失败");
17          //7. 释放资源
18         stem.close();
19         conn.close();

 1 package sqldemo;
 2  
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8  
 9 public class main {
10  
11     public static void main(String[] args) {
12         //声明Connection对象
13         Connection con;
14         //驱动程序名
15         String driver = "com.mysql.jdbc.Driver";
16         //URL指向要访问的数据库名mydata
17         String url = "jdbc:mysql://localhost:3306/sqltestdb";
18         //MySQL配置时的用户名
19         String user = "root";
20         //MySQL配置时的密码
21         String password = "123456";
22         //遍历查询结果集
23         try {
24             //加载驱动程序
25             Class.forName(driver);
26             //1.getConnection()方法，连接MySQL数据库！！
27             con = DriverManager.getConnection(url,user,password);
28             if(!con.isClosed())
29                 System.out.println("Succeeded connecting to the Database!");
30             //2.创建statement类对象，用来执行SQL语句！！
31             Statement statement = con.createStatement();
32             //要执行的SQL语句
33             String sql = "select * from emp";
34             //3.ResultSet类，用来存放获取的结果集！！
35             ResultSet rs = statement.executeQuery(sql);
36             System.out.println("-----------------");
37             System.out.println("执行结果如下所示:"); 
38             System.out.println("-----------------"); 
39             System.out.println("姓名" + "\t" + "职称"); 
40             System.out.println("-----------------"); 
41              
42             String job = null;
43             String id = null;
44             while(rs.next()){
45                 //获取stuname这列数据
46                 job = rs.getString("job");
47                 //获取stuid这列数据
48                 id = rs.getString("ename");
49  
50                 //输出结果
51                 System.out.println(id + "\t" + job);
52             }
53             rs.close();
54             con.close();
55         } catch(ClassNotFoundException e) {  
56             //数据库驱动类异常处理
57             System.out.println("Sorry,can`t find the Driver!");  
58             e.printStackTrace();  
59             } catch(SQLException e) {
60             //数据库连接失败异常处理
61             e.printStackTrace(); 
62             }catch (Exception e) {
63             // TODO: handle exception
64             e.printStackTrace();
65         }finally{
66             System.out.println("数据库数据成功获取！！");
67         }
68     }
69  
70 }