java Database Connectivity（java语言连接数据库）
JDBC的本质是什么？JDBC是sun公司指定的一套接口（interface）
接口都有调用者和实现者。
面向接口调用、面向接口写实现类，这都属于面向接口编程。
为什么要面向接口编程？ 解耦合：降低程序的耦合度，提高程序的扩展力。
多态机制就是非常典型的：面向抽象对象。（不要面向具体编程）
建议使用：
Animal a = new cat();
Animal b = new dog();
public void feed(Animal a){//面向父类型对象
}
不建议使用：
dog d = new dog();
cat c = new cat();
public void feed(dog a){
}
jdbc添加/删除/修改public static void main(String[] args) {
ResourceBundle bundle = ResourceBundle.getBundle("jdbc");
String driver = bundle.getString("driver");
String url = bundle.getString("url");
String username = bundle.getString("username");
String password = bundle.getString("password");
Statement stat = null;
Connection conn = null;
try{
Class.forname(driver);
conn = DriverManager.getConnection(url,username,password);
stat = conn.createStatment();
//String sql = "添加/删除/修改";
String sql = "insert into s_student(noo,namee,sex,age) values(5,'张三','n',20)";
int coun = stat.executeUpdate(sql);
system.out.prientln(count == 1 ? "添加成功" : "添加失败");
}catch(Exception e) {
e.printStackTrace();
}finally {
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (stat != null) {
try {
stat.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
jdbc查询
public static void main(String[] args) {
ResourceBundle bundle = ResourceBundle.getBundle("jdbc");
String driver = bundle.getString("driver");
String url = bundle.getString("url");
String username = bundle.getString("username");
String password = bundle.getString("password");
Statement stat = null;
Connection conn = null;
try{
Class.forname(driver);
conn = DriverManager.getConnection(url,username,password);
stat = conn.createStatment();
//String sql = "添加/删除/修改";
String sql = "select * from s_student";
int coun = stat.executeQuery(sql);
while(coun.next()){
String noo = resu.getString("noo");
String namee = resu.getString("namee");
String sex = resu.getString("sex");
String age = resu.getString("age");
System.out.println(noo+","+namee+","+sex+","+age);
}
}catch(Exception e) {
e.printStackTrace();
}finally {
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (stat != null) {
try {
stat.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
