在resource文件下创建db.properties文件内容为
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/jdbc?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=true
username=root
password=1234
创建基础类BaseDao.java引入properties文件内容
package com.peng.dao;
import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;
public class BaseDao {
private static String driver;
private static String url;
private static String username;
private static String password;
static {
Properties properties = new Properties();
InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
try {
properties.load(is);
} catch (IOException e) {
e.printStackTrace();
}
driver=properties.getProperty("driver");
url=properties.getProperty("url");
username=properties.getProperty("username");
password=properties.getProperty("password");
}
public static Connection GetConnection() throws Exception {
Connection connection=null;
Class.forName(driver);
connection = DriverManager.getConnection(url, username, password);
return connection;
}
//查询公共方法
public static ResultSet execute(Connection connection, PreparedStatement preparedStatement,ResultSet resultSet,String sql,Object[] params) throws SQLException {
preparedStatement = connection.prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
//setObject占位符从1开始，但是Object[]数组从0开始
preparedStatement.setObject(i+1,params[i]);
}
resultSet = preparedStatement.executeQuery();
return resultSet;
}
//增删改公共方法
public static int execute(Connection connection,String sql,PreparedStatement preparedStatement,Object[] params) throws SQLException {
preparedStatement = connection.prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
//setObject占位符从1开始，但是Object[]数组从0开始
preparedStatement.setObject(i+1,params[i]);
}
int update = preparedStatement.executeUpdate(sql);
return update;
}
//释放资源
public static boolean close(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet) {
boolean flog=true;
if(resultSet!=null){
try {
resultSet.close();
resultSet=null;
} catch (SQLException e) {
e.printStackTrace();
flog=false;
}}
if(preparedStatement!=null){
try {
preparedStatement.close();
preparedStatement=null;
} catch (SQLException e) {
e.printStackTrace();
flog=false;
}}
if(connection!=null){
try {
connection.close();
connection=null;
} catch (SQLException e) {
e.printStackTrace();
flog=false;
}
}
return flog;
}
}
