JDBC快速入門(附Java通過jar包連接MySQL數據庫)

 

•通過jar包連接mysql數據庫

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•下載jar包

Java 連接 MySQL 需要驅動包，官網下載地址為MySQL驅動包官網下載，選擇適合的jar包版本進行安裝

(記得安裝的地址，下面導入包時會用到)

•通過build path導入

在想要連接數據庫的項目名上右鍵->Build Path->Configure Build Path

 打開另一個頁面后，點擊Libraries(箭頭所示)

選擇Add External JARs…，選擇我們要添加的jar包(即上面安裝的地址)導入，Apply----Apply and Close即可。

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•JDBC連接數據庫的步驟

1：注冊驅動(Driver)

2：創建數據庫連接（Connection）

3:   定義SQL語句

4:  創建SQL命令發送器Statement

5：通過Statement發送SQL命令並得到結果

6：處理SQL結果

7：關閉數據庫資源

package JDBCtest;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class JDBCDemo {
    public static void main(String[] args) throws Exception {
        // 1. 注冊驅動
        Class.forName("com.mysql.jdbc.Driver");//Mysql 5之后這句可以不用寫，會自動填充

        // 2.獲取連接
        String url = "jdbc:mysql://127.0.0.1:3306/test";
        String username = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url, username, password);

        // 3.定義sql
        String sql = "select * from student";

        // 4.獲取執行sql的對象Statement
        Statement statement = connection.createStatement();

        // 5.執行sql
        ResultSet rs = statement.executeQuery(sql);
        
        //6.處理結果，ResultSet類用來存放獲取的結果集
        String sno = null;
        String sname = null;
        int age = 0;
        String cno = null;
        int num = 0;
        System.out.println("sno" + "\t" + "sname" + "\t" + "age" + "\t" + "cno" + "\t" + "num");
        while (rs.next()) {
            sno = rs.getString("sno");
            sname = rs.getString("sname");
            age = rs.getInt("age");
            cno = rs.getString("cno");
            num = rs.getInt("num");
            System.out.println(sno + "\t" + sname + "\t" + age + "\t" + cno + "\t" + num);
        }
        //7.釋放資源
        rs.close();
        statement.close();
        connection.close();
    }
}

將所查詢的數據保存到ArrayList中(方便上傳到網站等一系列的操作)

①測試類

package JDBCtest;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;

public class Demo {

    public static void main(String[] args) throws Exception {

        // 創建List
        ArrayList<Account> list = new ArrayList<Account>();
        // 加載驅動
        Class.forName("com.mysql.jdbc.Driver");
        // 創建連接
        String url = "jdbc:mysql:///test";
        String username = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url, username, password);
        // sql語句
        String sql = "select * from account";
        // 獲取執行sql語句的Statement
        Statement statement = connection.createStatement();
        // 執行sql
        ResultSet rs = statement.executeQuery(sql);
        while (rs.next()) {
            Account ac = new Account();
            ac.setAname(rs.getString("aname"));
            ac.setMoney(rs.getInt("money"));
            list.add(ac);
        }
        // 釋放資源
        statement.close();
        connection.close();
        for (Account a : list) {
            a.get();
        }
    }
}

②Account類

package JDBCtest;

public class Account {
    private String aname;
    private int money;

    public void get() {
        // TODO Auto-generated method stub
        System.out.println(aname + " " + money);
    }

    public void setAname(String aname) {
        this.aname = aname;
    }

    public void setMoney(int money) {
        this.money = money;
    }
}