文章目录
一、工具类的编写
public class JDBCUtils {
private static final String driverClassName;
private static final String url;
private static final String user;
private static final String password;
static{
driverClassName = "com.mysql.cj.jdbc.Driver";
url = "jdbc:mysql://localhost:3306/databasetest?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";
user = "root";
password = "root";
}
/**
* 注册驱动的方法
*/
public static void loadDriver(){
try{
Class.forName(driverClassName );
} catch (ClassNotFoundException e){
e.printStackTrace();
}
}
/**
* 获得连接的方法
*/
public static Connection getConnection(){
Connection conn = null;
try{
//将驱动一并注册
loadDriver();
//获得连接
conn = DriverManager.getConnection(url, user, password);
} catch(Expection e){
e.printStackTrace();
}
return conn;
}
/**
* 释放资源的方法
*/
public static void release(Statement stmt, Connection conn){
if(stmt != null){
try{
stmt.close();
}catch(SQLException e){
e.printStackTrace();
}
stmt = null;
}
if(conn != null){
try{
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
conn = null;
}
}
public static void release(ResultSet rs, Statement stmt, Connection conn){
if(rs != null){
try{
rs.close();
}catch(SQLException e){
e.printStackTrace();
}
rs = null;
}
if(stmt != null){
try{
stmt.close();
}catch(SQLException e){
e.printStackTrace();
}
stmt = null;
}
if(conn != null){
try{
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
conn = null;
}
}
}
二、调用工具类的代码
public class JDBCDemo{
/**
* 查询操作：实用工具类
*/
public void demo1(){
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try{
//获得连接
conn = JDBCUtils.getConnection();
//创建执行SQL语句的对象
stmt = conn.createStatement();
//编写SQL
String sql = "select * from user";
//执行查询
rs = stmt.executeQuery(sql);
//遍历结果集
while(rs.next()){
System.out.println(rs.getInt("id")+" "+rs.getString("name"));
}
}catch(Exception e){
e.printStackTrace();
}finally{
//释放资源
JDBCUtils.release(rs, stmt, conn);
}
}
}
内容比较多，看的太累了，先跳过，等学完了再来更新。。。