Introducing the core driver package mysql
1, tools
public class BaseDao {
static Properties proper;
static String driver;
static String url;
static String username;
static String password;
Connection conn;
static{
init();
}
public static void init(){
proper = new Properties();
InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("database.properties");
try {
proper.load(is);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
driver = proper.getProperty("driver");
url = proper.getProperty("url");
username = proper.getProperty("username");
password = proper.getProperty("password");
}
public Connection getConnection(){
Connection conn = null;
try {
Class.forName(driver);
System.out.println("加载数据库成功!");
conn = DriverManager.getConnection(url, username, password);
System.out.println("链接数据库成功!");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
public void closeConnection(Connection conn , Statement state , ResultSet rs){
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(state != null){
try {
state.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public int exceuteUpdate(String sql, Object patame[]){
PreparedStatement ps = null;
int num = 0;
conn = getConnection();
try {
ps = conn.prepareStatement(sql);
if(patame != null){
for(int i = 0; i < patame.length ; i ++){
ps.setObject(i+1, patame[i]);
}
}
num = ps.executeUpdate();
} catch (Exception e) {
// TODO: handle exception
} finally {
closeConnection(conn, ps, null);
}
System.out.println("num:"+num);
return num;
}
}
2, the definition of CRUD interfaces
public interface UserInterface {
public int InsterMethod(User user);
public int UpdateMethod(User user);
public int DeleteMethod(User user);
public User FillAll();
}
3, the implementation class
public class UserInterfaceDaoImpl extends BaseDao implements UserInterface {
@Override
public int InsterMethod(User user) {
String sql = "insert into User values(?,?)";
Object obj[] = {user.username,user.password};
int num = exceuteUpdate(sql, obj);
return num;
}
@Override
public int UpdateMethod(User user) {
// TODO Auto-generated method stub
return 0;
}
@Override
public int DeleteMethod(User user) {
// TODO Auto-generated method stub
return 0;
}
@Override
public User FillAll() {
// TODO Auto-generated method stub
return null;
}
}
4, the entity class
public class User {
public String username;
public String password;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
5, the test class
public class javaDemo01 {
public static void main(String[] args) {
UserInterfaceDaoImpl uifdi = new UserInterfaceDaoImpl();
User user = new User();
user.setUsername("zhaoyun");
user.setPassword("123456");
uifdi.InsterMethod(user);
}
}
6, link database configuration file
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test
username=root
password=root
