• 首先使用如下SQL語句生成一個users表

create table users(
	id int primary key auto_increment,
	name varchar(40),
	password varchar(40),
	email varchar(60),
	birthday date
)character set utf8 collate utf8_general_ci;

insert into users(name,password,email,birthday) values('zs','123456','[email protected]','1980-12-04'
 
);
insert into users(name,password,email,birthday) values('lisi','123456','[email protected]','1981-12-04');
insert into users(name,password,email,birthday) values('wangwu','123456','[email protected]','1979-12-04');

• 主函式

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.
 
sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class JDBC {
    public static void main(String[] args) {
        query();
        insert();
        update();
        delete();
    }

    public static void query() {
        Connection conn = null;
        PreparedStatement pstmt =
 
 null;
        ResultSet rs = null;

        try {
            conn = DBUtils.getConnection();
            pstmt = conn.prepareStatement("select * from users");
            rs = pstmt.executeQuery();
            List<User> list = new ArrayList<>();
            while (rs.next()) {
                User u = new User();
                //ResultSet類中的一些方法，獲取各種型別的資料
                u.setId(rs.getInt("id"));
                u.setName(rs.getString("name"));
                u.setPassword(rs.getString("password"));
                u.setBirthday(rs.getDate("birthday"));
                u.setEmail(rs.getString("email"));
                list.add(u);
            }
            for (User user : list) {
                System.out.println(user);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtils.closeAll(rs, pstmt, conn);
        }
    }

    public static void update() {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DBUtils.getConnection();
            pstmt = conn.prepareStatement("update users set name = ?,password = ?,email = ? where id = ?");
            //PreparedStatement類中的一些方法，設定SQL語句中問號位置的值
            pstmt.setString(1, "jerry");
            pstmt.setString(2, "123");
            pstmt.setString(3, "[email protected]");
            pstmt.setInt(4, 3);

            int i = pstmt.executeUpdate();
            if (i > 0) {
                System.out.println("update success");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtils.closeAll(null, pstmt, conn);
        }
    }

    public static void insert() {
        Connection conn = null;
        PreparedStatement pstmt = null;

        try {
            conn = DBUtils.getConnection();
            pstmt = conn.prepareStatement("insert into users values(?,?,?,?,?)");
            //PreparedStatement類中的一些方法，設定SQL語句中問號位置的值
            pstmt.setInt(1, 4);
            pstmt.setString(2, "tom");
            pstmt.setString(3, "333");
            pstmt.setString(4, "[email protected]");
            pstmt.setString(5, "2018-10-10");

            int i = pstmt.executeUpdate();
            if (i > 0) {
                System.out.println("insert success");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtils.closeAll(null, pstmt, conn);
        }
    }

    public static void delete() {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DBUtils.getConnection();
            pstmt = conn.prepareStatement("delete from users where id = ?");
            pstmt.setInt(1,4);//刪除id為4的記錄

            int id = pstmt.executeUpdate();
            if (id>0){
                System.out.println("delete success");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            DBUtils.closeAll(null,pstmt,conn);
        }
    }
}

• 輸出結果如下：

User{id=1, name='zs', password='123456', email='[email protected]', birthday=1980-12-04}
User{id=2, name='lisi', password='123456', email='[email protected]', birthday=1981-12-04}
User{id=3, name='wangwu', password='123456', email='[email protected]', birthday=1979-12-04}
insert success
update success
delete success

• 其中用到的Users類

import java.util.Date;

public class User {
    private int id;
    private String name;
    private String password;
    private String email;
    private Date birthday;
    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 getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getEmail(String email) {
        return this.email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

• 其中用到的DBUtils類

import java.sql.*;
import java.util.ResourceBundle;

public class DBUtils {
    private static String url;
    private static String username;
    private static String password;

    static{
        //此物件是用於載入dbinfo.properties檔案中的資料
        ResourceBundle rb = ResourceBundle.getBundle("dbinfo");
        url = rb.getString("url");//檔案中的資訊以字典的形式儲存
        username = rb.getString("username");
        password = rb.getString("password");

        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    //得到連線的方法
    public static Connection getConnection() throws Exception{
        return DriverManager.getConnection(url, username, password);
    }

    //關閉資源的方法
    public static void closeAll(ResultSet rs, PreparedStatement pstmt, Connection conn){
        //關閉資源
        if(rs!=null){
            try {
                rs.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            rs = null;
        }
        if(pstmt!=null){
            try {
                pstmt.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            pstmt = null;
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            conn = null;
        }
    }
}