JDBC笔记

JDBC

//加载驱动
Class.forName("oracle.jdbc.OracleDriver");
Class.forName("com.mysql.jdbc.Driver");

//获取数据库连接
String url = "jdbc:oracle:thin:@127.0.0.1:1521:jiangwenwen";
String user = "hr";
String password = "qwertyui";
conn = DriverManager.getConnection(url, user, password);

String url = "jdbc:mysql://192.168.235.138:3306/Game";
String user = "root";
String password = "qwertyui";
conn = DriverManager.getConnection(url, user, password);
注释掉bind（服务器）
授权
重启数据库

//准备发送执行sql语句
Connection conn=null;
Statement stem=null;
String sql="insert into departments values(departments_seq.nextval,'招商部',120,1700)";
stem =conn.createStatement();
int n =  stem.executeUpdate(sql);

Connection conn=null;
PreparedStatement ps =null;
ResultSet rs=null;
String sql="select * from departments where department_id>? and location_id>?";
String sql = "INSERT INTO users (phone_number, pwd) VALUES (?,?)";
ps=conn.prepareStatement(sql);
ps.setInt(1, 40);
ps.setInt(2, 1700);
ps.execute();

//增删改操作
int n = ps.executeUpdate();
if(n>0){
    System.out.println("数据库添加操作成功");
}else{
    System.out.println("数据库添加操作失败");
}

//查询操作
while (rs.next()) {
    Dept dept =new Dept();
    dept.setD_id(rs.getInt("department_id"));//
    dept.setD_name(rs.getString("department_name"));
    dept.setM_id(rs.getInt("manager_id"));
    dept.setLo_id(rs.getInt("location_id"));
    list.add(dept);
}

//关闭连接

数据库连接池

C3P0

ComboPooledDataSource cpds = new ComboPooledDataSource();

cpds.setDriverClass( "oracle.jdbc.OracleDriver" );

cpds.setJdbcUrl( "jdbc:oracle:thin:@127.0.0.1:1521:jiangwenwen" );

cpds.setUser("jiangwenwen");   

cpds.setPassword("qwertyui");




QueryRunner qr = new QueryRunner(C3P0Util.getDataSource());

//插入数据

String sql = "INSERT INTO USERS(id,username,Password,Gender,Email,Telephone,INTRODUCE,active_code,state,register_time)
"

+ "VALUES (id_seq.nextval,?,?,?,?,?,?,?,?,?)";

qr.update(sql,user.getUsername(), user.getPassword(), user.getGender(), user.getEmail(),user.getTelephone(), user.getIntroduce(), user.getActive_code(), user.getState(),
user.getRegister_time());



//查询数据

return qr.query("select * from users where active_code = ?",new BeanHandler<Users>(Users.class),active_code);

//更新数据

qr.update("update users set state=1 where active_code=?",active_code);

qr.update("update users set password=?,gender=?,telephone=? where id = ?",user.getPassword(),user.getGender(),user.getTelephone(),user.getId());

​
Dbutil处理

//批处理
//高维代表循环次数，低维代表每次的参数
Object[][] params = new Object[orderItems.size()][];
for(int i=0;i<params.length;i++) {
			
//数组中第一个参数代表主单id，第二个参数商品id，第三个参数是商品的购买数量
    params[i] = new Object[]{order.getId(),orderItems.get(i).getBook().getId(),orderItems.get(i).getBuy_num()};

}

qr.batch(ManagerThreadLocal.getConnection(),"INSERT INTO orderitem VALUES(?,?,?)", params);

/*
 *  使用QueryRunner类,实现对数据表的
 *  insert delete update
 *  调用QueryRunner类的方法 update (Connection con,String sql,Object...param)
 *  Object...param 可变参数,Object类型,SQL语句会出现?占位符
 *  数据库连接对象,自定义的工具类传递
 */
public class QueryRunnerDemo {
	private static Connection con = JDBCUtilConfig.getConnection();

	public static void main(String[] args) throws SQLException {
		// insert();
		update();
		// delete();
	}

	/*
	 * 定义方法,使用QueryRunner类的方法delete将数据表的数据删除
	 */
	public static void delete() throws SQLException {
		// 创建QueryRunner类对象
		QueryRunner qr = new QueryRunner();
		// 写删除的SQL语句
		String sql = "DELETE FROM sort WHERE sid=?";
		// 调用QueryRunner方法update
		int row = qr.update(con, sql, 8);
		System.out.println(row);
		/*
		 * 判断insert,update,delete执行是否成功 对返回值row判断 if(row>0) 执行成功
		 */
		DbUtils.closeQuietly(con);
	}

	/*
	 * 
	 * public static void update()throws SQLException{ //创建QueryRunner类对象
	 * QueryRunner qr = new QueryRunner(); //写修改数据的SQL语句 String sql =
	 * "UPDATE sort SET sname=?,sprice=?,sdesc=? WHERE sid=?"; //定义Object数组,存储?中的参数
	 * Object[] params = {"花卉",100.88,"情人节玫瑰花",4}; //调用QueryRunner方法update int row =
	 * qr.update(con, sql, params); System.out.println(row);
	 * DbUtils.closeQuietly(con); }
	 * 
	 * /* 定义方法,使用QueryRunner类的方法update向数据表中,添加数据
	 */
	public static void insert() throws SQLException {
		// 创建QueryRunner类对象
		QueryRunner qr = new QueryRunner();
		String sql = "INSERT INTO sort (sname,sprice,sdesc)VALUES(?,?,?)";
		// 将三个?占位符的实际参数,写在数组中
		Object[] params = { "体育用品", 289.32, "购买体育用品" };
		// 调用QueryRunner类的方法update执行SQL语句
		int row = qr.update(con, sql, params);
		System.out.println(row);
		DbUtils.closeQuietly(con);
	}
}

 /**
 * QueryRunner数据查询操作
 * 	调用QueryRunner类方法query(Connection con,String sql,ResultSetHandler r,Object..params)
 * 		ResultSetHandler r 结果集的处理方式，传递ResultSetHandler接口实现类
 * 		Object...params sql语句的?占位符
 *  
 * 注意：query方法返回值，返回的是T 泛型，具体返回值类型，跟随结果集处理方式变化
 * */
public class QueryRunnerDemo02 {
	private static Connection con = JDBCUtilConfig.getConnection();
	public static void main(String[] args) throws SQLException {
		//ArrayHandler();
		//arrayListHandler();
		//beanHandler();
		//beanListHandler();
		//columnListHandler();
		//scalarHandler();
		//mapHandler();
		mapListHandler();
	}
	
	/**	
	 * 结果集第一种处理方法，ArrayHandler
	 * 将结果第一行存储到对象数组中Object[]
	 * @throws SQLException 
	 * */
	public static void ArrayHandler() throws SQLException {
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT * FROM sort";
		//调用query执行查询，传递连接对象，SQL语句，结果集处理方式的实现类 
		//返回对象数组
		Object[] result = qr.query(con, sql,new ArrayHandler());
		for (Object obj : result) {
			System.out.println(obj);
		}
	}
	
	/**
	 * 结果集的第二种处理方法，ArrayListHandler
	 * 将结果集的每一行，封装到对象数组中，出现很多对象数组
	 * 对象数组存储到List集合
	 * @throws SQLException 
	 * */
	public static void arrayListHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql  = "SELECT * FROM sort";
		//调用query方法，结果集处理的参数上，传递实现类ArrayListHandler
		//方法返回值 每行是一个数组
		List<Object[]> result = qr.query(con, sql, new ArrayListHandler());
		//集合的遍历
		for (Object[] objs : result) {
			for (Object obj : objs) {
				System.out.print(obj+"	");
			}
			System.out.println();
		}
	}
	/**
	 * 结果集的第三种处理方法BeanHandler
	 * 将结果集的第一行数据，封装为JavaBean对象
	 * 注意：被封装成数据到JavaBean对象，Sort类必须有空参构造
	 * @throws SQLException 
	 * */
	public static void beanHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT * FROM sort";
		//调用方法，传递结果集实现BeanHandler
		//BeanHandler(Class<T> type)
		Sort s = qr.query(con, sql,new BeanHandler<Sort>(Sort.class));
		System.out.println(s);
	} 
	
	/**
	 * 结果集第四种处理方法，BeanListHandler
	 * 将数据结果集的每一行数据，封装为JavaBean对象
	 * 多个JavaBean对象封装到List集合中
	 * @throws SQLException 
	 * */
	public static void beanListHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT * FROM sort";
		//调用方法传递结果集的实现类BeanListHandler
		//BeanListHandler(Class<T> type)
		List<Sort> list = qr.query(con, sql, new BeanListHandler<Sort>(Sort.class));
		for (Sort s : list) {
			System.out.println(s);
		}
	}
	
	/**
	 * 结果集第五种处理方法，ColumnListHandler
	 * 结果集，指定列的数据，存储到List集合中
	 * List<Object> 每个列数据类型不同
	 * @throws SQLException 
	 * */
	public static void columnListHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT * FROM sort";
		//调用方法query，传递结果集实现类ColumnListHandler
		//实现类构造方法，使用字符串的列名
		List<Object> list = qr.query(con, sql, new ColumnListHandler<Object>("sname"));
		for (Object obj : list) {
			System.out.println(obj);
		}
	}
	/**
	 * 结果集第六种处理方法、
	 * 对于查询后，只有一个结果
	 * @throws SQLException 
	 * */
	public static void scalarHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT COUNT(*) FROM sort";
		//调用方法query,传递结果集处理类ScalarHandler
		long count = qr.query(con,sql,new ScalarHandler<Long>());
		System.out.println(count);
	}
	
	/**
	 * 结果集的第七种处理方式，MapHandler
	 * 将结果集第一行数据，封装到Map集合中
	 * Map<键，值> 键：列名 值：这列数据
	 * @throws SQLException 
	 * */
	public static void mapHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT * FROM sort";
		//调用方法query，传递结果集实现类MapHandler
		//返回值：Map集合，Map接口实现类 泛型
		Map<String,Object> map = qr.query(con, sql,new MapHandler());
		for (String key : map.keySet()) {
			System.out.println(key+"..."+map.get(key));
		}
	}
	/**
	 * 结果集第八种处理方法，MapListHandler
	 * 将结果集每一行存储到Map集合，键：列名 值：数据
	 * Map集合过多，存储到List集合
	 * @throws SQLException 
	 * */
	public static void mapListHandler() throws SQLException{
		QueryRunner qr = new QueryRunner();
		String sql = "SELECT * FROM sort";
		//调用方法query，传递结果集实现类MapListHander
		//返回值List集合，存储的是Map集合
		List<Map<String, Object>> list = qr.query(con, sql,new MapListHandler());
		for (Map<String, Object> map : list) {
			for (String key : map.keySet()) {
				System.out.print(key+"..."+map.get(key));
			}
			System.out.println();
		}
	}
}

JDBC如何实现模糊查询

//第一种
String sql = "select studentname, age, phone, address, other from customer  where studentname like ? "; 

pstmt.setString(1, "%" + customername + "%" );    

//第二种

String sql = "select customercode, customername, phone, address, relationman, other from customer"
                + " where customername like "%"?"%" ";
                
pstmt.setString(1, customername);