dbutils工具類

此工具類解決代碼冗餘問題。

DBUtils工具類對JDBC封裝。
核心類：QueryRunner類，提供兩個方法： 
1、update() ：DML操作
2、query() ：DQL操作，針對返回的結果集做了再次封裝，重點要學習返回對象集合

JavaBean 是java中一個可以重用的組件。本質就是一個類。
定義javabean規範：
1）類必須是public修飾
2）類中屬性必須是private
3）類中必須有無參構造
4）私有屬性必須封裝get/set方法

注意，需要將commons-dbutils-1.7.jar 添加到項目中。

添加數據的代碼：

package dbutils;

import java.sql.SQLException;
import java.util.Scanner;

import org.apache.commons.dbutils.QueryRunner;

import com.mchange.v2.c3p0.ComboPooledDataSource;
/**
 * 添加操作
 * @author Ven
 *
 */
public class Insert2 {
	public static void main(String[] args) {
		
		Scanner input=new Scanner(System.in);
		System.out.print("請輸入ID:");
		int eid = input.nextInt();
		System.out.print("請輸入姓名:");
		String ename = input.next();
		System.out.print("請輸入密碼:");
		String epwd = input.next();
		System.out.print("請輸入年齡:");
		int eage = input.nextInt();
		System.out.print("請輸入生日:");
		String ebirthday = input.next();
		System.out.print("請輸入電話:");
		String etel = input.next();
		//編寫sql語句
		String sql="INSERT INTO employee(eid,ename,epwd,eage,ebirthday,etel)" + 
				"VALUES(?,?,?,?,?,?)";
		//1.創建QueryRunner類對象
		QueryRunner qrunner=new QueryRunner(new ComboPooledDataSource());
		try {
			//2.執行sql語句
			int r = qrunner.update(sql, eid,ename,epwd,eage,ebirthday,etel);
			//3.處理結果
			if (r>0) {
				System.out.println("成功");
			}else {
				System.out.println("失敗");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}

	}
}

Employee類(便於封裝重用)：

package dbutils;

public class Employee {
/*	類必須是public修飾
	類中屬性必須是private
	類中必須有無參構造
	私有屬性必須封裝get/set方法
*/
	private int eid;
	private String ename;
	private int eage;
	private String epwd;
	private String ebirthday;
	private String etel;
	//封裝
	public int getEid() {
		return eid;
	}
	public void setEid(int eid) {
		this.eid = eid;
	}
	public String getEname() {
		return ename;
	}
	public void setEname(String ename) {
		this.ename = ename;
	}
	public int getEage() {
		return eage;
	}
	public void setEage(int eage) {
		this.eage = eage;
	}
	public String getEpwd() {
		return epwd;
	}
	public void setEpwd(String epwd) {
		this.epwd = epwd;
	}
	public String getEbirthday() {
		return ebirthday;
	}
	public void setEbirthday(String ebirthday) {
		this.ebirthday = ebirthday;
	}
	public String getEtel() {
		return etel;
	}
	public void setEtel(String etel) {
		this.etel = etel;
	}
	
	//類必須是public修飾,必須有無參構造
	public Employee() {}
	public Employee(int eid,String ename,String epwd,int eage,String ebirthday,String etel) {
		this.eid=eid;
		this.ename = ename;
		this.eage = eage;
		this.epwd = epwd;
		this.ebirthday = ebirthday;
		this.etel = etel;
	}
	
	
}

package dbutils;
import java.sql.SQLException;
import java.util.List;
import java.util.Scanner;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import com.mchange.v2.c3p0.ComboPooledDataSource;
/**
 * 查詢多條記錄操作
 * @author Ven
 *
 */
public class SelectMore {
	public static void main(String[] args) {
		String sql="SELECT * FROM employee";
		QueryRunner qrunner=new QueryRunner(new ComboPooledDataSource());
		try {
			List<Employee> list = qrunner.query(sql, new BeanListHandler<Employee>(Employee.class));
			
			System.out.println("ID\t姓名\t密碼\t年齡\t生日\t\t\t電話");
			for (Employee employee : list) {
				System.out.println(employee.getEid()+"\t"+employee.getEname()+"\t"+employee.getEpwd()+"\t"+employee.getEage()+"\t"+employee.getEbirthday()+"\t"+employee.getEtel());
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}