jdbc筆記(一) 使用Statement對單表的CRUD操作
阿新 • • 發佈：2019-01-01
jdbc連線mysql並執行簡單的CRUD的步驟：
1.註冊驅動（需要丟擲/捕獲異常）
Class.forName("com.mysql.jdbc.Driver");
2.建立連線需要丟擲/捕獲異常）
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/testdb", "root", "Danny2036");
3.建立statement
statement = connection.createStatement();
4.建立sql語句
String sql = "insert into user values(10, \"noname\", 31)";
5.執行sql語句，如果是查詢需要用ResultSet接收結果集
int affectrows = statement.executeUpdate(sql); System.out.println(affectrows);
6.關閉資源
if (statement != null) { statement.close(); } if (connection != null) { connection.close(); }
————————————————————————分割線——————————————————————————————————
最後貼出全部程式碼（包括insert，selectOne和selectAll）
package com.colin.dao; import java.sql.*; public class JdbcTest { /** * 插入語句 * @param id 主鍵id int * @param name 姓名 String * @param age 年齡 int */ public static void update(int id, String name, int age) throws SQLException {long starttime = System.currentTimeMillis(); Connection connection = null; Statement statement = null; try { Class.forName("com.mysql.jdbc.Driver"); connection = DriverManager.getConnection( "jdbc:mysql://localhost:3306/testdb", "root", "Danny2036"); statement = connection.createStatement(); String sql = "update user set name = \'" + name + "\', age = "+ age +" where id = " + id; System.out.println(sql); int affectrows = statement.executeUpdate(sql); System.out.println(affectrows); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { if (connection != null) { connection.close(); } if (statement != null) { statement.close(); } } System.out.println(System.currentTimeMillis() - starttime); } public static void selectOne(int id) throws ClassNotFoundException, SQLException { Statement statement = null; Connection connection = null; try { // 註冊驅動 Class.forName("com.mysql.jdbc.Driver"); // 建立連線 connection = DriverManager.getConnection( "jdbc:mysql://localhost:3306/testdb", "root", "Danny2036" ); // 建立statement statement = connection.createStatement(); // 定義sql語句 String sql = "SELECT id, name, age FROM user where id = " + id; // 執行sql語句並獲得結果 ResultSet resultSet = statement.executeQuery(sql); // 遍歷結果集 while (resultSet.next()) { int idResult = (int) resultSet.getInt("id"); String nameResult = (String) resultSet.getString("name"); int ageResult = (int) resultSet.getInt("age"); System.out.println(idResult + "\t" + nameResult + "\t" + ageResult); } } finally { if (statement != null) { statement.close(); } if (connection != null) { connection.close(); } } } public static void selectAll() throws ClassNotFoundException, SQLException { Statement statement = null; Connection connection = null; try { // 註冊驅動 Class.forName("com.mysql.jdbc.Driver"); // 建立連線 connection = DriverManager.getConnection( "jdbc:mysql://localhost:3306/testdb", "root", "Danny2036" ); // 建立statement statement = connection.createStatement(); // 定義sql語句 String sql = "SELECT id, name, age FROM user"; // 執行sql語句並獲得結果 ResultSet resultSet = statement.executeQuery(sql); // 遍歷結果集 while (resultSet.next()) { int idResult = (int) resultSet.getInt("id"); String nameResult = (String) resultSet.getString("name"); int ageResult = (int) resultSet.getInt("age"); System.out.println(idResult + "\t" + nameResult + "\t" + ageResult); } } finally { if (statement != null) { statement.close(); } if (connection != null) { connection.close(); } } } public static void main(String[] args) throws SQLException, ClassNotFoundException { selectAll(); } /* // 向上拋異常的方式 public static void main(String[] args) throws ClassNotFoundException, SQLException { long starttime = System.currentTimeMillis(); Connection connection = null; Statement statement = null; try { //註冊驅動 Class.forName("com.mysql.jdbc.Driver"); //建立連線 connection = DriverManager.getConnection( "jdbc:mysql://localhost:3306/testdb", "root", "Danny2036"); //建立statement statement = connection.createStatement(); //定義sql String sql = "insert into user values(10, \"noname\", 31)"; //執行sql，如果是查詢需返回結果集 int affectrows = statement.executeUpdate(sql); System.out.println(affectrows); } finally { //關閉資源 if (statement != null) { statement.close(); } if (connection != null) { connection.close(); } } System.out.println("總執行時間： " + (System.currentTimeMillis() - starttime)); } */ /* // 捕獲異常的方式 public static void main(String[] args) throws SQLException { long starttime = System.currentTimeMillis(); Statement statement = null; Connection connection = null; try { // 註冊驅動 Class.forName("com.mysql.jdbc.Driver"); // 建立連線 connection = DriverManager.getConnection( "jdbc:mysql://localhost:3306/testdb?useSSL=true", "root", "Danny2036"); // 建立statement statement = connection.createStatement(); // 定義sql String sql = "insert into user values(9, \"ahaha\", 22)"; // 執行sql，如果是查詢，遍歷結果集 int affectrows = statement.executeUpdate(sql); System.out.println(affectrows); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { // 關閉資源 if (statement != null) { statement.close(); } if (connection != null) { connection.close(); } } System.out.println("總用時 ： " + (System.currentTimeMillis() - starttime)); } */ }
——————————————————**********最後附上bean程式碼***********————————————————————
package com.colin.bean; public class User { private int id; private String name; private int age; public User(int id, String name, int age) { this.id = id; this.name = name; this.age = age; } public User(String name, int age) { this.name = name; this.age = age; } 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 int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", age=" + age + '}'; } }