JDBC入門筆記1
基本概念
1.概念
Java DataBase Connectiving Java 資料庫連線 , Java語言操作資料庫
*JDBC 本質:其實是官方(sun公司)定義的一套操作所有關係型資料庫的規則,即介面。各個資料庫廠商去實現這套介面,提供資料庫驅動jar包。我們可以使用這套介面(JDBC)程式設計,真正執行的程式碼是驅動jar包中的實現類。
2.快速入門
步驟:
1. 匯入驅動jar包 mysql-connector-java-5.1.37-bin.jar
1.複製mysql-connector-java-5.1.37-bin.jar到專案的libs目錄下
2.右鍵-->Add As Library
2.註冊驅動
Class.forName("com.mysql.cj.jdbc.Driver");
3.獲取資料庫連線物件
connection conn= DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/day1?serverTimezone=UTC","賬戶","密碼");
4.定義SQL語句
String sql="select *from customer";
5.獲取執行sql語句物件(Statement)
Statement stat=conn.createStatement();
6.執行sql語句返回結果
Resultset result=stat.executeQuery(sql);
7.釋放資源
result.close();
stat.close();
con.close();
示例程式碼:
package get_data;
import java.sql.*;
import java.util.ArrayList;
import java.util.Iterator;
public class get_data_class {
public static void main(String[] args) {
Connection conn=null;
Statement stat=null;
ResultSet resultSet=null;
ArrayList
try {
//註冊驅動
Class.forName("com.mysql.cj.jdbc.Driver");
//建立連結物件
conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/day1?serverTimezone=UTC", "root", "zhangyu");
//sql語句
String sql="select *from customer";
//sql連線物件
stat= conn.createStatement();
//執行sql語句
resultSet = stat.executeQuery(sql);
while(resultSet.next()){ int id=resultSet.getInt("id"); String name=resultSet.getString("name"); String qq=resultSet.getString("qq"); String phone=resultSet.getString("phone"); int dept_id=resultSet.getInt("dept_id"); float salary=resultSet.getFloat("salary"); customer customer = new customer(); customer.setId(id); customer.setName(name); customer.setQq(qq); customer.setPhone(phone); customer.setDept_id(dept_id); customer.setSalary(salary); customerArrayList.add(customer); } System.out.println(customerArrayList);
// for (int i=0;i<customerArrayList.size();i++){
// System.out.println(customerArrayList.get(i));
// }
// for (customer cus:customerArrayList){
// System.out.println(cus);
// }
Iterator
while(iterator.hasNext()){
System.out.println(iterator.next());
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}catch (SQLException e) {
e.printStackTrace();
}finally {
if (resultSet!=null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(stat!=null){
try {
stat.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
public class customer {
private int id;
private String name;
private String qq;
private String phone;
private int dept_id;
private float salary;
public customer() {
}
public customer(int id, String name, String qq, String phone, int dept_id, float salary) {
this.id = id;
this.name = name;
this.qq = qq;
this.phone = phone;
this.dept_id = dept_id;
this.salary = salary;
}
@Override
public String toString() {
return "customer{" +
"id=" + id +
", name='" + name + '\'' +
", qq='" + qq + '\'' +
", phone='" + phone + '\'' +
", dept_id=" + dept_id +
", salary=" + salary +
'}';
}
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 String getQq() {
return qq;
}
public void setQq(String qq) {
this.qq = qq;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public int getDept_id() {
return dept_id;
}
public void setDept_id(int dept_id) {
this.dept_id = dept_id;
}
public float getSalary() {
return salary;
}
public void setSalary(float salary) {
this.salary = salary;
}
}