JavaWeb 使用DBUtils实现增删改查

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1、创建C3p0Utils类

创建cn.itcast.jdbc.utils包

代码如下：

package cn.itcast.jdbc.utils;
import javax.sql.DataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
public class C3p0Utils {
	private static DataSource ds;
	static {
		ds = new ComboPooledDataSource();
	}
	public static DataSource getDataSource() {
		return ds;
	}
}

2、创建DBUtilsDao类

在src目录下，创建一个cn.itcast.jdbc.demo的包，在该包下创建一个DBUtilsDao类

代码如下：

package cn.itcast.jdbc.demo;
import java.sql.SQLException;
import java.util.List;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import cn.itcast.chapter10.example.User;
import cn.itcast.jdbc.utils.C3p0Utils;
public class DBUtilsDao {
	// 查询所有，返回List集合
	public List findAll() throws SQLException {
		// 创建QueryRunner对象
		QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource());
		// 写SQL语句
		String sql = "select * from user";
		// 调用方法
		List list = (List) runner.query(sql,
                     new BeanListHandler(User.class));
		return list;
	}
	// 查询单个，返回对象
	public User find(int id) throws SQLException {
		// 创建QueryRunner对象
		QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource());
		// 写SQL语句
		String sql = "select * from user where id=?";
		// 调用方法
		User user = (User) runner.query(sql, 
                 new BeanHandler(User.class), new Object[] { id });
		return user;
	}
	// 添加用户的操作
	public Boolean insert(User user) throws SQLException {
		// 创建QueryRunner对象
		QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource());
		// 写SQL语句
		String sql = "insert into user (name,password) values (?,?)";
		// 调用方法
		int num = runner.update(sql,
				new Object[] { user.getName(), user.getPassword() });
		if (num > 0)
			return true;
		return false;
	}
	// 修改用户的操作
	public Boolean update(User user) throws SQLException {
		// 创建QueryRunner对象
		QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource());
		// 写SQL语句
		String sql = "update  user set name=?,password=? where id=?";
		// 调用方法
		int num = runner.update(sql, new Object[] { user.getName(),
                     user.getPassword(),user.getId() });
		if (num > 0)
			return true;
		return false;
	}
	// 删除用户的操作
	public Boolean delete(int id) throws SQLException {
		// 创建QueryRunner对象
		QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource());
		// 写SQL语句
		String sql = "delete from user where id=?";
		// 调用方法
		int num = runner.update(sql, id);
		if (num > 0)
			return true;
		return false;
	}
}

3、创建测试类

在cn.itcast.jdbc.demo包中创建测试类DBUtilsDaoTest类

代码如下：

package cn.itcast.jdbc.demo;
import java.sql.SQLException;
import java.util.List;
import cn.itcast.chapter10.example.User;
public class DBUtilsDaoTest1 {
	private static DBUtilsDao dao = new DBUtilsDao();
	
	public static void testInsert() throws SQLException {
		User user = new User();
		user.setName("zhaoliu");
		user.setPassword("666666");
		boolean b = dao.insert(user);
		System.out.println("testInsert:"+b);
	}
	
	public static void testupdate() throws SQLException {
		User user = new User();
		user.setName("zhaoqi");
		user.setPassword("666777");
		user.setId(1);
		boolean b = dao.update(user);
		System.out.println("testupdate:"+b);
	}
	
	public static void testdelete() throws SQLException {
		boolean b = dao.delete(4);
		System.out.println("testdelete:"+b);
	}
	
	public static void testfindById() throws SQLException {
		User user = dao.find(2);
		System.out.println(user.getId() + "," + user.getName() + ","
				+ user.getPassword());
	}
	
	public static void testfindAll() throws SQLException {
		List<User> list = dao.findAll();
		for(User user : list) {
		System.out.println(user.getId() + "," + user.getName() + ","
				+ user.getPassword());
		}
	}
	public static void main(String[] args) throws SQLException {
		testInsert();
		testupdate();
		testdelete();
		testfindById();
		testfindAll();
	}
}

以上代码由多个测试函数组成，依次为：插入、修改、删除、根据id查询、查询所有

4、执行测试类

1.数据表user原始数据如下：

执行后结果如下：

之中插入和删除都是针对第四个数据进行的操作，所以没有显现