step1:从mysql官网下载jdbc链接库->点击此处
step2:然后把库文件添加到JAVA项目中
step3:java代码链接mysql数据库(详细见代码)
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class MySQL_test {
static final String DB_URL = "jdbc:mysql://localhost:3306/lock_System";
// Database credentials
static final String USER = "username";
static final String PASS = "password";
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try {
// STEP 1: Register JDBC driver
Class.forName("com.mysql.jdbc.Driver");
// STEP 2: Open a connection
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
// STEP 3: Execute a query
System.out.println("Creating statement...");
stmt = conn.createStatement();
String sql;
sql = "SELECT id, password FROM Pwd_manager";
ResultSet rs = stmt.executeQuery(sql);
// STEP 4: Extract data from result set
while (rs.next()) {
// Retrieve by column name
String pwd = rs.getString("password");
if (pwd.equals("hello")) {
System.out.println("First: " + pwd);
}
}
// STEP 5: Clean-up environment
rs.close();
stmt.close();
conn.close();
} catch (SQLException se) {
// Handle errors for JDBC
se.printStackTrace();
} catch (Exception e) {
// Handle errors for Class.forName
e.printStackTrace();
} finally {
// finally block used to close resources
try {
if (stmt != null)
stmt.close();
} catch (SQLException se2) {
}// nothing we can do
try {
if (conn != null)
conn.close();
} catch (SQLException se) {
se.printStackTrace();
} // end finally try
} // end try
}
}