Java基础之数据库增删改查

增加：

public boolean insert(Admin admin){
		String sql = "INSERT INTO admin(adminName,password,createtime)VALUES(?,?,?)";
		try {
				Connection connection = DBUtils.getConnection();
				PreparedStatement ps = connection.prepareStatement(sql);
				ps.setString(1,admin.getAdminName());
				ps.setString(2,admin.getPassword());
				ps.setDate(3,new java.sql.Date(admin.getCreatetime().getTime()));
				if(ps.executeUpdate() > 0){
					ps.close();
					connection.close();
					return true;
				}
		} catch (SQLException e) {
			// TODO Auto-generated atch block
			e.printStackTrace();
		}
		return false;
	}

查询：

	public List<Admin> findByAll(){
		String sql = "SELECT * FROM admin";
		List<Admin> list = new ArrayList<Admin>();
		Connection connection = null;
		try {
			connection = DBUtils.getConnection();
			PreparedStatement ps = connection.prepareStatement(sql);
			ResultSet rs = ps.executeQuery();
			while(rs.next()){
				System.out.println(rs.getInt(1) + " " + rs.getString(2) + " " + rs.getString(3));
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return list;
	}

public Admin getById(int id){
		String sql = "SELECT id,adminName,password,createtime,updatetime,lastlogintime FROM admin"
				+ "	where id = ?";
		try {
			Connection connection = DBUtils.getConnection();
			PreparedStatement ps = connection.prepareStatement(sql);
			ps.setInt(1, id);
			ResultSet rs = ps.executeQuery();
			if (rs.next()) {
				Admin admin = new Admin();
				admin.setId(rs.getInt(1));
				admin.setAdminName(rs.getString(2));
				admin.setPassword(rs.getString(3));
				admin.setCreatetime(rs.getDate(4));
				admin.setUpdatetime(rs.getDate(5));
				admin.setLastlogintime(rs.getDate(6));
				return admin;
			}else{
				return null;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}

删除：

public boolean delete(Integer[] ids) {
		String sql = "DELETE FROM admin WHERE id IN (";
		for (Integer integer : ids) {
			sql += "?,";
		}
		sql = sql.substring(0, sql.length() - 1) + ')';
		try {
			Connection connection = DBUtils.getConnection();
			PreparedStatement ps = connection.prepareStatement(sql);
			for(int i = 1;i <= ids.length;i++){
				ps.setInt(i, ids[i - 1]);
			}
			if(ps.executeUpdate() > 0){
				return true;
			}
		} catch (SQLException e) {
			// TODO: handle exception
		}
		return false;
	}

修改：（先查后改）

public boolean update(Admin admin){
		Admin admin2 = this.getById(admin.getId());
		System.out.println(admin.getAdminName());
		if (admin2 != null) {
			try {
				String sql = "UPDATE admin SET adminName = ?,password=?,updatetime=?,lastlogintime=? WHERE id = ?";
				Connection connection = DBUtils.getConnection();
				PreparedStatement ps = connection.prepareStatement(sql);
				ps.setString(1, admin.getAdminName());
				ps.setString(2, admin.getPassword());
				ps.setDate(3,new java.sql.Date(admin.getUpdatetime().getTime()));
				ps.setDate(4,new java.sql.Date(admin.getLastlogintime().getTime()));
				ps.setInt(5, admin.getId());
				if (ps.executeUpdate() > 0) {
					System.out.println("1！！");
					return true;
				}
			} catch (Exception e) {
				// TODO: handle exception
				e.printStackTrace();
			}
		}
		return false;
	}