jdbc——mysql的增、删、改、查测试

jdbc——mysql的增、删、改、查测试

工具：myeclipse
驱动包：https://dev.mysql.com/downloads/connector/j/5.1.html
加入驱动包后》》

准备数据库和表：

CREATE test IF NOT EXISTS user3 
CHARACTER SET charset=utf8;

CREATE TABLE user3
     (
     id SMALLINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
     username VARCHAR(20) NOT NULL,
     password VARCHAR(32) NOT NULL,
     age TINYINT NOT NULL DEFAULT 18,
     sex BOOLEAN
     );

操作步骤：
1. 加载驱动程序
2. 获得数据库连接
3. 通过数据库连接操作数据库

---

以下是测试代码：
select.java

package mysql;

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

/**
 * jdbc连接mysql数据库
 * 查询测试
 * @author https://blog.csdn.net/qq_32953185/
 */
public class select {

    static final String URL="jdbc:mysql://127.0.0.1:3306/test";
    static final String USER="root";
    static final String PASSWORD="admin";

    public static void main(String[] args) {

        try {
            //加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //获得数据库连接
            Connection conn = DriverManager.getConnection(URL,USER,PASSWORD);
            //通过数据库连接操作数据库
            Statement stmt = conn.createStatement();

            String sql = "select id,username,password,age,sex from user3;";
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next())
            {
                System.out.println(rs.getInt("id")+","+rs.getString("username")
                +","+rs.getString("password")+","+rs.getInt("age")+","+rs.getInt("sex"));
            }

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

}

测试结果：
输出了表的所有记录

insert.java

package mysql;

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

/**
 * jdbc连接mysql数据库
 * 插入测试
 * @author https://blog.csdn.net/qq_32953185/
 */
public class insert {

    static final String URL="jdbc:mysql://127.0.0.1:3306/test";
    static final String USER="root";
    static final String PASSWORD="admin";

    public static void main(String[] args) {
        try {
            //加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //获得数据库连接
            Connection conn = DriverManager.getConnection(URL,USER,PASSWORD);
            //通过数据库连接操作数据库
            Statement stmt = conn.createStatement();

            String sql = "insert into user3 values("+"null,?,?,?,?)";
            PreparedStatement  ptmt = conn.prepareStatement(sql);

            //插入小明的记录
            ptmt.setString(1, "小明"); //id
            ptmt.setString(2, "12345"); //username
            ptmt.setInt(3, 20); //age
            ptmt.setInt(4, 1);  //sex
            ptmt.execute(); //执行
            System.out.println("执行完毕!");

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }
}

测试结果：
insert了一个小明的记录

update.java

package mysql;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * jdbc连接mysql数据库
 * 更新测试
 * @author https://blog.csdn.net/qq_32953185/
 */
public class update {

    static final String URL="jdbc:mysql://127.0.0.1:3306/test";
    static final String USER="root";
    static final String PASSWORD="admin";

    public static void main(String[] args) {
        try {
            //加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //获得数据库连接
            Connection conn = DriverManager.getConnection(URL,USER,PASSWORD);
            //通过数据库连接操作数据库
            Statement stmt = conn.createStatement();

            String sql = " update user3 set username=?,password=?,age=?,sex=?"+
                         " where username=?";
            PreparedStatement  ptmt = conn.prepareStatement(sql);

            //把username为小明改成小日月
            ptmt.setString(1, "小日月"); //username
            ptmt.setString(2, "54321"); //password
            ptmt.setInt(3, 21); //age
            ptmt.setInt(4, 1);  //sex
            ptmt.setString(5, "小明");    //where username=小明
            ptmt.execute(); //执行
            System.out.println("执行完毕!");

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }
}

测试结果：
把小明的username修改成小日月

delete.java

package mysql;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * jdbc连接mysql数据库
 * 删除测试
 * @author https://blog.csdn.net/qq_32953185/
 */
public class delete {
    static final String URL="jdbc:mysql://127.0.0.1:3306/test";
    static final String USER="root";
    static final String PASSWORD="admin";

    public static void main(String[] args) {
        try {
            //加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //获得数据库连接
            Connection conn = DriverManager.getConnection(URL,USER,PASSWORD);
            //通过数据库连接操作数据库
            Statement stmt = conn.createStatement();

            String sql = " delete from user3"+
                         " where username=?";
            PreparedStatement  ptmt = conn.prepareStatement(sql);

            //删除小日月的记录
            ptmt.setString(1, "小日月"); //name
            ptmt.execute(); //执行
            System.out.println("执行完毕!");

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

测试结果：
把小日月的记录删除了