jdbc簡單增刪改查代碼

JDBC連接MYSQL數據庫：

package cn.outofmemory.test;

import java.sql.Connection;
import java.sql.DriverManager;

public class Mysql {
    public static void main(String arg[]) {
        try {
            Connection con = null; //定義一個MYSQL鏈接對象
            Class.forName("com.mysql.jdbc.Driver").newInstance(); //MYSQL驅動
            con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test", "root", "root"); //鏈接本地MYSQL
            System.out.print("yes");
        } catch (Exception e) {
            System.out.print("MYSQL ERROR:" + e.getMessage());
        }

    }
}

Class.forName(“com.mysql.jdbc.Driver”).newInstance(); 我們鏈接的是MYSQL數據庫，所以需要一個MYSQL的數據庫驅動，如果你的環境中沒有安裝， 可以下載：mysql-connector-java-5.1.17-bin.jar JAR包，然後放進jdk1.6.0_37\jre\lib\ext 重啓eclispe 就可以在JRE系統庫中看到。

con = DriverManager.getConnection;(“jdbc:mysql://127.0.0.1:3306/test”, “root”, “root”); 是鏈接數據庫的語句， 返回Connection con;對象。參數格式：(“jdbc:mysql://ip:端口/數據庫名稱”, 用戶名,密碼)

寫入一條數據

package main;

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

public class Mysql {

    /**
     * 入口函數
     * @param arg
     */
    public static void main(String arg[]) {
        try {
            Connection con = null; //定義一個MYSQL鏈接對象
            Class.forName("com.mysql.jdbc.Driver").newInstance(); //MYSQL驅動
            con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test", "root", "root"); //鏈接本地MYSQL

            Statement stmt; //創建聲明
            stmt = con.createStatement();

            //新增一條數據
            stmt.executeUpdate("INSERT INTO user (username, password) VALUES ('init', '123456')");
            ResultSet res = stmt.executeQuery("select LAST_INSERT_ID()");
            int ret_id;
            if (res.next()) {
                ret_id = res.getInt(1);
                System.out.print(ret_id);
            }

        } catch (Exception e) {
            System.out.print("MYSQL ERROR:" + e.getMessage());
        }

    }
}

stmt.executeUpdate INSERT; DELETE; UPDATE;語句都用executeUpdate函數來操作 stmt.executeQuery SELECT;語句都用stmt.executeQuery函數來操作 ResultSet res = stmt.executeQuery;(“select LAST;_INSERT_ID()”); 查詢最後插入數據的ID號，返回ResultSet res;對象

刪除和更新數據

package main;

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

public class Mysql {

    /**
     * 入口函數
     * @param arg
     */
    public static void main(String arg[]) {
        try {
            Connection con = null; //定義一個MYSQL鏈接對象
            Class.forName("com.mysql.jdbc.Driver").newInstance(); //MYSQL驅動
            con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test", "root", "root"); //鏈接本地MYSQL

            Statement stmt; //創建聲明
            stmt = con.createStatement();

            //新增一條數據
            stmt.executeUpdate("INSERT INTO user (username, password) VALUES ('init', '123456')");
            ResultSet res = stmt.executeQuery("select LAST_INSERT_ID()");
            int ret_id;
            if (res.next()) {
                ret_id = res.getInt(1);
                System.out.print(ret_id);
            }

            //刪除一條數據
            String sql = "DELETE FROM user WHERE id = 1";
            long deleteRes = stmt.executeUpdate(sql); //如果爲0則沒有進行刪除操作，如果大於0，則記錄刪除的條數
            System.out.print("DELETE:" + deleteRes);

            //更新一條數據
            String updateSql = "UPDATE user SET username = 'xxxx' WHERE id = 2";
            long updateRes = stmt.executeUpdate(updateSql);
            System.out.print("UPDATE:" + updateRes);

        } catch (Exception e) {
            System.out.print("MYSQL ERROR:" + e.getMessage());
        }

    }
}

刪除和更新數據都使用stmt.executeUpdate函數。 刪除和更新數據都會返回一個Long的結果，如果爲0，則刪除或者更新失敗，如果大於0則是操作刪除的記錄數

查詢語句

package main;

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

public class Mysql {

    /**
     * 入口函數
     * @param arg
     */
    public static void main(String arg[]) {
        try {
            Connection con = null; //定義一個MYSQL鏈接對象
            Class.forName("com.mysql.jdbc.Driver").newInstance(); //MYSQL驅動
            con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test", "root", "root"); //鏈接本地MYSQL

            Statement stmt; //創建聲明
            stmt = con.createStatement();

            //新增一條數據
            stmt.executeUpdate("INSERT INTO user (username, password) VALUES ('init', '123456')");
            ResultSet res = stmt.executeQuery("select LAST_INSERT_ID()");
            int ret_id;
            if (res.next()) {
                ret_id = res.getInt(1);
                System.out.print(ret_id);
            }

            //刪除一條數據
            String sql = "DELETE FROM user WHERE id = 1";
            long deleteRes = stmt.executeUpdate(sql); //如果爲0則沒有進行刪除操作，如果大於0，則記錄刪除的條數
            System.out.print("DELETE:" + deleteRes);

            //更新一條數據
            String updateSql = "UPDATE user SET username = 'xxxx' WHERE id = 2";
            long updateRes = stmt.executeUpdate(updateSql);
            System.out.print("UPDATE:" + updateRes);

            //查詢數據並輸出
            String selectSql = "SELECT * FROM user";
            ResultSet selectRes = stmt.executeQuery(selectSql);
            while (selectRes.next()) { //循環輸出結果集
                String username = selectRes.getString("username");
                String password = selectRes.getString("password");
                System.out.print("\r\n\r\n");
                System.out.print("username:" + username + "password:" + password);
            }

        } catch (Exception e) {
            System.out.print("MYSQL ERROR:" + e.getMessage());
        }

    }
}

查詢語句使用stmt.executeQuery函數

• rs.absolute() //絕對位置，負數表示從後面數
• rs.first()第一條
• rs.last()最後一條
• rs.previoust()前一條
• rs.next()後一條
• rs.beforeFirst()第一條之前
• rs.afterLast()最後之後
• rs.isFirst(),rs.isLast(),rs.isBeforeFirst(),rs.isAfterLast