ResultSet的介绍与使用

article/2025/10/1 7:27:33

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jdbc连接以及出现的异常处理
Jdbc工具类
ResultSet的介绍与使用
jdbc中的sql注入
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jdbc管理事务

ResultSet

ResultSet是我们使用jdbc连接时，查询的一个返回结果集,ResultSet resultSet = stmt.executeQuery(sql),下面就使用例子介绍ResultSet的使用

例子是通过jdbc连接查account表中的数据，然后用实体类Account封装起来，返回这个类的集合。

jdbc工具类代码

package com.lingaolu.Utils;import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.*;
import java.util.Properties;/*** @author 林高禄* @create 2020-06-23-11:12*/
public class JdbcUtils {private static String driver;private static String url;private static String userName;private static String pw;static{try {Properties p = new Properties();ClassLoader classLoader = JdbcUtils.class.getClassLoader();// 这个路径相对于src的路径来说URL resource = classLoader.getResource("com/lingaolu/file/jdbc.properties");String path = resource.getPath();p.load(new FileReader(path));driver = p.getProperty("driver");url = p.getProperty("url");userName = p.getProperty("user");pw = p.getProperty("password");Class.forName(driver);} catch (IOException e) {e.printStackTrace();} catch (ClassNotFoundException e) {e.printStackTrace();}}public static Connection createConnection() throws SQLException {return DriverManager.getConnection(url, userName, pw);}public static void close(Statement stmt,Connection con){if(null != stmt){try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}if(null != con){try {con.close();} catch (SQLException e) {e.printStackTrace();}}}public static void close(ResultSet set,Statement s,Connection con){if(null != set){try {set.close();} catch (SQLException e) {e.printStackTrace();}}close(s,con);}
}

Account实体类代码

package com.lingaolu.jdbcConnector;/*** @author 林高禄* @create 2020-06-24-8:28*/
public class Account {private int id;private String name;private double balance;private int myAge;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public double getBalance() {return balance;}public void setBalance(double balance) {this.balance = balance;}public int getMyAge() {return myAge;}public void setMyAge(int myAge) {this.myAge = myAge;}@Overridepublic String toString() {return "Account{" +"id=" + id +", name='" + name + '\'' +", balance=" + balance +", myAge=" + myAge +'}';}
}

测试Demo3的代码

package com.lingaolu.jdbcConnector;import com.lingaolu.Utils.JdbcUtils;import java.sql.*;
import java.util.ArrayList;
import java.util.List;/*** @author 林高禄* @create 2020-06-23-17:27*/
public class Demo3 {public static void main(String[] args) {String sql = "select * from account";List<Account> accounts = fineAccount(sql);accounts.forEach(System.out::println);System.out.println("----------------------------------");sql = "select * from account where name='张三'";accounts = fineAccount(sql);accounts.forEach(System.out::println);}public static List<Account> fineAccount(String sql){Connection con = null;Statement stmt = null;ResultSet resultSet = null;List<Account> rerurnList = new ArrayList<>();try {con = JdbcUtils.createConnection();stmt = con.createStatement();resultSet = stmt.executeQuery(sql);Account acc = null;while(resultSet.next()){// 引号里的字段要与表里的一样int id = resultSet.getInt("id");String name = resultSet.getString("name");double balance = resultSet.getDouble("balance");int age = resultSet.getInt("age");acc = new Account();acc.setId(id);acc.setName(name);acc.setBalance(balance);acc.setMyAge(age);rerurnList.add(acc);}} catch (SQLException e) {e.printStackTrace();}finally {JdbcUtils.close(resultSet,stmt,con);}return rerurnList;}
}

表中的数据

运行输出：

Account{id=1, name='张三', balance=500.0, myAge=17}
Account{id=2, name='李四', balance=1000.0, myAge=16}
Account{id=7, name='张三', balance=600.0, myAge=19}
Account{id=11, name='林帅', balance=20000.0, myAge=18}
----------------------------------
Account{id=1, name='张三', balance=500.0, myAge=17}
Account{id=7, name='张三', balance=600.0, myAge=19}