JDBC数据库连接
import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class MyConnection { static Statement statement = null
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class MyConnection {
static Statement statement = null;
static PreparedStatement preStat = null;
static ResultSet resultSet = null;
static Connection con = null;
public static void main(String[] args) {
MyConnection mycon = new MyConnection();
Connection con = mycon.getConnection();
// ********************数据遍历
// Statement用来执行sql语句
try {
statement = con.createStatement();
// 要执行的SQL语句
String sql = "select * from Student";
// 结果集
resultSet = statement.executeQuery(sql);
// 遍历数据
while (resultSet.next()) {
String Sid = resultSet.getString(1);
String Sname = resultSet.getString(2);
String Sage = resultSet.getString(3);
String Ssex = resultSet.getString(4);
String Szhuanye = resultSet.getString(5);
System.out.println("Sid:" + Sid + " Sname:" + Sname
+ " Sage:" + Sage + " Ssex:" + Ssex + " Szhuanye:"
+ Szhuanye);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// ************执行增删改 字符串的拼接 *********
// insert into student valuse('"+Sid+"','"+Sname+"'.......);
// ****************预处理执行增删改**************
String insert = "insert into student values(?,?,?,?,?)";
String update = "update student set Sname=? where Sid=?";
String delete = "delete from student where Sid=?";
// 增加数据
try {
preStat = con.prepareStatement(insert);
// 这里可能还要判断一下数据库的约束条件
preStat.setString(1, "100080");
preStat.setString(2, "我试试");
preStat.setString(3, "100");
preStat.setString(4, "男");
preStat.setString(5, "100080");
// 执行sql语句
preStat.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// **********更新数据
try {
preStat = con.prepareStatement(update);
preStat.setString(1, "更改");
preStat.setString(2, "100080");
preStat.executeUpdate();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
// **********删除数据
try {
preStat = con.prepareStatement(delete);
preStat.setString(1, "100080");
preStat.executeUpdate();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
// ************************预处理语句PreparedStatement 查询数据
try {
preStat = con.prepareStatement("select * from Student where Sid=?");
// 设置参数 表示 第一个参数 为100002
preStat.setString(1, "100080");
// 执行预处理语句
resultSet = preStat.executeQuery();
// 遍历数据
while (resultSet.next()) {
String Sid = resultSet.getString(1);
String Sname = resultSet.getString(2);
String Sage = resultSet.getString(3);
String Ssex = resultSet.getString(4);
String Szhuanye = resultSet.getString(5);
System.out.println("Sid:" + Sid + " Sname:" + Sname
+ " Sage:" + Sage + " Ssex:" + Ssex + " Szhuanye:"
+ Szhuanye);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// 数据库连接方法
public Connection getConnection() {
// 驱动程序名
String driver = "com.mysql.jdbc.Driver";
// URL指向要访问的数据库名score
String url = "jdbc:mysql://localhost:3306/score?useUnicode=true&characterEncoding=UTF-8";
//注意score后面家的代码是指定编码 不知道 有可能乱码
// String url="jdbc:mysql://127.0.0.1:3306/score";
// MySQL配置时的用户名
String user = "root";
// MySQL配置时的密码
String password = "123456";
try {
// 加载驱动 通过名字把类的源数据对象加载到内存中
Class.forName(driver);
// 连续数据库
con = DriverManager.getConnection(url, user, password);
if (!con.isClosed())
System.out.println("数据库连接成功!");
} catch (Exception e) {
e.printStackTrace();
}
return con;
}
}

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Apple's latest releases of iOS18, iPadOS18 and macOS Sequoia systems have added an important feature to the Photos application, designed to help users easily recover photos and videos lost or damaged due to various reasons. The new feature introduces an album called "Recovered" in the Tools section of the Photos app that will automatically appear when a user has pictures or videos on their device that are not part of their photo library. The emergence of the "Recovered" album provides a solution for photos and videos lost due to database corruption, the camera application not saving to the photo library correctly, or a third-party application managing the photo library. Users only need a few simple steps

Hibernate polymorphic mapping can map inherited classes to the database and provides the following mapping types: joined-subclass: Create a separate table for the subclass, including all columns of the parent class. table-per-class: Create a separate table for subclasses, containing only subclass-specific columns. union-subclass: similar to joined-subclass, but the parent class table unions all subclass columns.

How to use MySQLi to establish a database connection in PHP: Include MySQLi extension (require_once) Create connection function (functionconnect_to_db) Call connection function ($conn=connect_to_db()) Execute query ($result=$conn->query()) Close connection ( $conn->close())

To handle database connection errors in PHP, you can use the following steps: Use mysqli_connect_errno() to obtain the error code. Use mysqli_connect_error() to get the error message. By capturing and logging these error messages, database connection issues can be easily identified and resolved, ensuring the smooth running of your application.

HTML cannot read the database directly, but it can be achieved through JavaScript and AJAX. The steps include establishing a database connection, sending a query, processing the response, and updating the page. This article provides a practical example of using JavaScript, AJAX and PHP to read data from a MySQL database, showing how to dynamically display query results in an HTML page. This example uses XMLHttpRequest to establish a database connection, send a query and process the response, thereby filling data into page elements and realizing the function of HTML reading the database.

Using the database callback function in Golang can achieve: executing custom code after the specified database operation is completed. Add custom behavior through separate functions without writing additional code. Callback functions are available for insert, update, delete, and query operations. You must use the sql.Exec, sql.QueryRow, or sql.Query function to use the callback function.

Through the Go standard library database/sql package, you can connect to remote databases such as MySQL, PostgreSQL or SQLite: create a connection string containing database connection information. Use the sql.Open() function to open a database connection. Perform database operations such as SQL queries and insert operations. Use defer to close the database connection to release resources.

JSON data can be saved into a MySQL database by using the gjson library or the json.Unmarshal function. The gjson library provides convenience methods to parse JSON fields, and the json.Unmarshal function requires a target type pointer to unmarshal JSON data. Both methods require preparing SQL statements and performing insert operations to persist the data into the database.
