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方法一
Class.forName(“com.mysql.cj.jdbc.Driver”); 需要抛出ClassNotFoundException异常 package com.javaee.code; import java.sql.*; /** *TestJdbc */ public class jdbcTest { public static String getMysql(){ String url = "jdbc:mysql://127.0.0.1:3306/test_db1";//定义url // 驱动名字 String driverName = "com.mysql.cj.jdbc.Driver"; // 查询语句 String sqlString = "SELECT * FROM employee limit 1"; String result = null; try { // 1 加载驱动(3种方法?) Class.forName(driverName);// 方法1 // 2 创建连接 Connection connection = DriverManager.getConnection(url,"root","123456"); // 3 通过连接获取statement Statement statement = connection.createStatement(); // 4 statement 做一些 增删改查 ResultSet resultSet = statement.executeQuery(sqlString); // 5 获取执行结果 while (resultSet.next()){ result = resultSet.getString(1); } } catch ( ClassNotFoundException | SQLException e) { result = e.toString(); //e.printStackTrace(); } return result; } public static void main(String args){ getMysql(); } } 方法二System.setProperty(“jdbc.drivers”, “com.mysql.cj.jdbc.Driver”); 出现SQLExceptionjava.sql.SQLException: No suitable driver found for jdbc:mysql://127.0.0.1:3306/test_db1 原因:之前tomcat的子目录lib下的jdbc包被我删,加上,解决! package com.javaee.code; import java.sql.*; /** *TestJdbc */ public class jdbcTest { public static String getMysql(){ String url = "jdbc:mysql://127.0.0.1:3306/test_db1";//定义url // 驱动名字 String driverName = "com.mysql.cj.jdbc.Driver"; // 查询语句 String sqlString = "SELECT * FROM employee limit 1"; String result = null; try { System.setProperty("jdbc.drivers",driverName);// 方法2 // 2 创建连接 Connection connection = DriverManager.getConnection(url,"root","123456"); // 3 通过连接获取statement Statement statement = connection.createStatement(); // 4 statement 做一些 增删改查 ResultSet resultSet = statement.executeQuery(sqlString); // 5 获取执行结果 while (resultSet.next()){ result = resultSet.getString(1); } } catch ( SQLException e) { result = e.toString(); //e.printStackTrace(); } return result; } public static void main(String args){ getMysql(); } } 方法三DriverManager.registerDriver(new com.mysql.jdbc.Driver()); package com.javaee.code; import java.sql.*; /** *TestJdbc */ public class jdbcTest { public static String getMysql(){ String url = "jdbc:mysql://127.0.0.1:3306/test_db1";//定义url // 驱动名字 //String driverName = "com.mysql.cj.jdbc.Driver"; // 查询语句 String sqlString = "SELECT * FROM employee limit 1"; String result = null; try { // 1 加载驱动(3种方法?) //Class.forName(driverName);// 方法1 //System.setProperty("jdbc.drivers",driverName);// 方法2 DriverManager.registerDriver(new com.mysql.jdbc.Driver());//方法3 // 2 创建连接 Connection connection = DriverManager.getConnection(url,"root","123456"); // 3 通过连接获取statement Statement statement = connection.createStatement(); // 4 statement 做一些 增删改查 ResultSet resultSet = statement.executeQuery(sqlString); // 5 获取执行结果 while (resultSet.next()){ result = resultSet.getString(1); } } catch ( SQLException e) {//|ClassNotFoundException(方法1) result = e.toString(); //e.printStackTrace(); } return result; } public static void main(String args){ getMysql(); } } |
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