本章提供了有关如何使用DBUtils库创建简单JDBC应用程序的示例。这将向您展示如何打开数据库连接,执行SQL查询以及显示输出。
将以下示例复制并粘贴到MainApp.java中,按如下所示进行编译和运行-
MainApp.java
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import org.apache.commons.dbutils.DbUtils; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.ResultSetHandler; import org.apache.commons.dbutils.handlers.BeanHandler; public class MainApp { //JDBC 驱动程序名称和数据库 URL static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://localhost:3306/emp"; //数据库帐号密码 static final String USER = "root"; static final String PASS = "admin"; public static void main(String[] args) throws SQLException { Connection conn = null; QueryRunner queryRunner = new QueryRunner(); //第一步:注册JDBC驱动 DbUtils.loadDriver(JDBC_DRIVER); //第二步:打开连接 System.out.println("Connecting to database..."); conn = DriverManager.getConnection(DB_URL, USER, PASS); //第三步:创建一个 ResultSet Handler 来处理 Employee Bean ResultSetHandler<Employee> resultHandler = new BeanHandler<Employee>(Employee.class); try { Employee emp = queryRunner.query(conn, "SELECT * FROM employees WHERE first=?", resultHandler, "Sumit"); //显示信息 System.out.print("ID: " + emp.getId()); System.out.print(", Age: " + emp.getAge()); System.out.print(", First: " + emp.getFirst()); System.out.println(", Last: " + emp.getLast()); } finally { DbUtils.close(conn); } } }
Employee.java
public class Employee { private int id; private int age; private String first; private String last; public int getId() { return id; } public void setId(int id) { this.id = id; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getFirst() { return first; } public void setFirst(String first) { this.first = first; } public String getLast() { return last; } public void setLast(String last) { this.last = last; } }
现在让无涯教程编译以上示例,如下所示:
C:\>javac MainApp.java Employee.java C:\>
当您运行 MainApp 时,它会产生以下输出-
C:\>java MainApp Connecting to database... ID: 103, Age: 28, First: Sumit, Last: Learnfk C:\>
祝学习愉快!(内容编辑有误?请选中要编辑内容 -> 右键 -> 修改 -> 提交!)