package com.lideng.util;
import com.lideng.entity.User;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
public class DBUtil {
/*静态加载*/
static {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
/**
* 返回连接对象
* @return Connection对象
*/
public static Connection getConnection(){
try {
return DriverManager.getConnection("jdbc:mysql://localhost:3306/test?characterEnconding=UTF-8", "root", "root");
} catch (SQLException e) {
e.printStackTrace();
return null;
}
}
/**
*
* @param sql 执行的sql语句
* @param args 参数
* @return true代表执行成功 反之亦然
*/
public static boolean executeUpdate(String sql,Object... args){
PreparedStatement ps =null;
try {
ps = getConnection().prepareStatement(sql);
for (int i=0;i
ps.setObject(i+1, args[i]);
}
int i = ps.executeUpdate();
return i>0;
} catch (SQLException e) {
e.printStackTrace();
return false;
}finally {
colse(ps);
}
}
/**
*
* @param sql
* @return 查询到的结果集
*/
public static List query(String sql){
List list=new ArrayList<>();
try {
PreparedStatement ps = getConnection().prepareStatement(sql);
ResultSet rs = ps.executeQuery();
while(rs.next()){
User u=new User(rs.getInt(1), rs.getString(2), rs.getString(3));
list.add(u);
}
return list;
} catch (SQLException e) {
e.printStackTrace();
return null;
}
}
/**
* 关闭连接
* @param autoCloseables
*/
public static void colse(AutoCloseable... autoCloseables){
for (AutoCloseable a:autoCloseables){
if (a!=null){
try {
a.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
