vggnet pytorch_Javaweb项目

vggnet pytorch_Javaweb项目VGG网络是在2014年由牛津大学著名研究组VGG(VisualGeometryGroup)提出。

大家好,又见面了,我是你们的朋友全栈君。如果您正在找激活码,请点击查看最新教程,关注关注公众号 “全栈程序员社区” 获取激活教程,可能之前旧版本教程已经失效.最新Idea2022.1教程亲测有效,一键激活。

Jetbrains全家桶1年46,售后保障稳定

对应百度飞桨页面

VGG网络是在2014年由牛津大学著名研究组VGG (Visual Geometry Group) 提出。

下载花分类数据集

import requests
import os
import time
import sys

Jetbrains全家桶1年46,售后保障稳定

class DownloadZip():
    def __init__(self, url):
        self.url = url

    def download(self):
        # 记录文件下载开始时间
        start = time.time()
        # 获取当前执行文件所在的工作目录
        cwd = os.getcwd()
        # 文件存放位置
        data_root = os.path.join(cwd, 'work')
        print(data_root)
        if not os.path.exists(data_root):
            os.mkdir(data_root)
        data_root = os.path.join(data_root, 'flower_data')
        if not os.path.exists(data_root):
            os.mkdir(data_root)
        # 获取文件名
        file_name = self.url.split('/')[-1]

        temp_size = 0

        res = requests.get(self.url, stream=True)
        # 每次下载数据大小
        chunk_size = 1024
        total_size = int(res.headers.get("Content-Length"))

        if res.status_code == 200:
            # 换算单位并打印
            print('[文件大小]:%0.2f MB' % (total_size / chunk_size / 1024))
            # 保存下载文件
            with open(os.path.join(data_root, file_name), 'wb') as f:
                for chunk in res.iter_content(chunk_size=chunk_size):
                    if chunk:
                        temp_size += len(chunk)
                        f.write(chunk)
                        f.flush()
                        # 花哨的下载进度部分
                        done = int(50 * temp_size / total_size)
                        # 调用标准输出刷新命令行,看到\r 回车符了吧
                        # 相当于把每一行重新刷新一遍
                        sys.stdout.write(
                            "\r[%s%s] %d%%" % ('█' * done, ' ' * (50 - done), 100 * temp_size / total_size))
                        sys.stdout.flush()
            # 避免上面\r 回车符,执行完后需要换行了,不然都在一行显示
            print()
            # 结束时间
            end = time.time()
            print('全部下载完成!用时%.2f 秒' % (end - start))
        else:
            print(res.status_code)
if not os.path.exists(os.path.join(os.getcwd(), 'work', 'flower_data', 'flower_photos.tgz')):
    zip_url = 'http://download.tensorflow.org/example_images/flower_photos.tgz'
    segmentfault = DownloadZip(zip_url)
    segmentfault.download()
import tarfile

def un_tgz(filename):
    tar = tarfile.open(filename)
    print(os.path.splitext(filename)[0])
    tar.extractall(os.path.join(os.path.splitext(filename)[0], '..'))
    tar.close()


if not os.path.exists(os.path.join(os.getcwd(), 'work', 'flower_data', 'flower_photos')):
    os.mkdir(os.path.join(os.getcwd(), 'work', 'flower_data', 'flower_photos'))
    un_tgz(os.path.join(os.getcwd(), 'work', 'flower_data', 'flower_photos.tgz'))

数据集划分成训练集train和验证集val

from shutil import copy, rmtree
import random
from tqdm import tqdm
def mk_file(file_path: str):
    if os.path.exists(file_path):
        # 如果文件夹存在,则先删除原文件夹在重新创建
        rmtree(file_path)
    os.makedirs(file_path)  # 创建文件夹


def train_val():
    # 创建随机种子,目的为了复现试验
    random.seed(0)
    # 验证集所占数据集的比重
    split_rate = 0.1

    cwd = os.getcwd()  # 获取当前执行文件所在的工作目录
    data_root = os.path.join(cwd, 'work', 'flower_data')
    origin_flower_path = os.path.join(data_root, 'flower_photos')
    assert os.path.exists(origin_flower_path), "path '{}' does not exist.".format(origin_flower_path)
    # 列表推导式(if是为了除去文件夹中的非文件夹)
    flowers_class = [cla for cla in os.listdir(origin_flower_path)
                     if os.path.isdir(os.path.join(origin_flower_path, cla))]
    print(flowers_class)
    # 创建训练集文件夹
    train_root = os.path.join(data_root, 'train')
    mk_file(train_root)

    # 创建测试集文件夹
    val_root = os.path.join(data_root, 'val')
    mk_file(val_root)

    for cla in flowers_class:
        mk_file(os.path.join(train_root, cla))
        mk_file(os.path.join(val_root, cla))

    for cla in flowers_class:
        cla_path = os.path.join(origin_flower_path, cla)
        images = os.listdir(cla_path)
        num = len(images)
        eval_index = random.sample(images, k=int(num*split_rate))
        for index, image in tqdm(enumerate(images)):
            if image in eval_index:
                image_path = os.path.join(cla_path, image)
                new_path = os.path.join(val_root, cla)
            else:
                image_path = os.path.join(cla_path, image)
                new_path = os.path.join(train_root, cla)
            copy(image_path, new_path)

    print('Processing of data_split done!')
if not os.path.exists(os.path.join(os.getcwd(), 'work', 'flower_data', 'train')):
    train_val()
print('Data ready!')

vggnet pytorch_Javaweb项目

该网络中的亮点: 通过堆叠多个3×3的卷积核来替代大尺度卷积核(在拥有相同感受野的前提下能够减少所需参数)。

论文中提到,可以通过堆叠两层3×3的卷积核替代一层5×5的卷积核,堆叠三层3×3的卷积核替代一层7×7的卷积核。下面给出一个示例:使用7×7卷积核所需参数,与堆叠三个3×3卷积核所需参数(假设输入输出特征矩阵深度channel都为C)

如果使用一层卷积核大小为7的卷积所需参数(第一个C代表输入特征矩阵的channel,第二个C代表卷积核的个数也就是输出特征矩阵的深度):

7∗7∗C∗C=49C27 *7*C*C=49C ^27∗7∗C∗C=49C*C

如果使用三层卷积核大小为3的卷积所需参数:

3∗3∗C∗C+3∗3∗C∗C+3∗3∗C∗C=27C23*3*C*C+3*3*C*C+3*3*C*C=27C*C ^23∗3∗C∗C+3∗3∗C∗C+3∗3∗C∗C=27C*C

经过对比明显使用3层大小为3×3的卷积核比使用一层7×7的卷积核参数更少

vggnet pytorch_Javaweb项目

 Pytorch实现部分代码

model.py

import torch
import torch.nn as nn


# # official pretrain weights
# model_urls = {
#     'vgg11': 'https://download.pytorch.org/models/vgg11-bbd30ac9.pth',
#     'vgg13': 'https://download.pytorch.org/models/vgg13-c768596a.pth',
#     'vgg16': 'https://download.pytorch.org/models/vgg16-397923af.pth',
#     'vgg19': 'https://download.pytorch.org/models/vgg19-dcbb9e9d.pth'
# }
# 上面这个参数都没有用,数据训练采用的是 1000,我们用的花分类的数据集只有五个类,输出的只有五个类
# predict 还是需要自己先训练一下

class VGG(nn.Module):
    def __init__(self, features, num_classes=1000, init_weights=False):
        super(VGG, self).__init__()
        self.features = features
        self.classifier = nn.Sequential(
            nn.Linear(512*7*7, 4096),
            nn.ReLU(inplace=True),
            nn.Dropout(p=0.5),
            nn.Linear(4096, 4096),
            nn.ReLU(inplace=True),
            nn.Dropout(p=0.5),
            nn.Linear(4096, num_classes),
        )
        if init_weights:
            self._initialize_weights()

    def _initialize_weights(self):
        for model in self.modules():
            if isinstance(model, nn.Conv2d):
                nn.init.xavier_uniform_(model.weight)
                if model.bias is not None:
                    nn.init.constant_(model.bias, 0)
            elif isinstance(model, nn.Linear):
                nn.init.xavier_uniform_(model.weight)
                nn.init.constant_(model.bias, 0)

    def forward(self, x):
        x = self.features(x)
        x = torch.flatten(x, start_dim=1)
        x = self.classifier(x)
        return x


def make_features(cfg: list):
    layer = []
    in_channels = 3
    for v in cfg:
        if v == 'M':
            layer += [nn.MaxPool2d(kernel_size=2, stride=2)]
        else:
            conv2d = nn.Conv2d(in_channels, v, kernel_size=3, padding=1)
            layer += [conv2d, nn.ReLU(True)]
            in_channels = v
    return nn.Sequential(*layer)  # 非关键字参数


cfgs = {
    'vgg11': [64, 'M', 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
    'vgg13': [64, 64, 'M', 128, 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
    'vgg16': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 'M', 512, 512, 512, 'M', 512, 512, 512, 'M'],
    'vgg19': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 256, 'M', 512, 512, 512, 512, 'M', 512, 512, 512, 512, 'M'],
}


def vgg(model_name="vgg16", **kwargs):
    assert model_name in cfgs, "Warning: model number {} not in cfgs dict!".format(model_name)
    cfg = cfgs[model_name]
    model = VGG(make_features(cfg), **kwargs)
    return model

train.py

import os
import json

import torch
import torch.nn as nn
from torchvision import transforms, datasets
import torch.optim as optim
from tqdm import tqdm

from model import vgg


def main():
    device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
    print("using {} device.".format(device))

    data_transform = {
        'train': transforms.Compose(
            [
                transforms.RandomResizedCrop(224),
                transforms.RandomHorizontalFlip(),
                transforms.ToTensor(),
                transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))
            ]
        ),
        'val': transforms.Compose(
            [
                transforms.Resize((224, 224)),
                transforms.ToTensor(),
                transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))
            ]
        )
    }
    data_root = os.path.abspath(os.path.join(os.getcwd(), '..'))
    image_path = os.path.join(data_root, 'AlexNet', 'flower_data')
    assert os.path.exists(image_path), "{} path does not exist.".format(image_path)
    train_dataset = datasets.ImageFolder(root=os.path.join(image_path, "train"),
                                         transform=data_transform["train"])

    train_num = len(train_dataset)

    flower_list = train_dataset.class_to_idx
    cla_dict = dict((val, key) for key, val in flower_list.items())
    json_str = json.dumps(cla_dict, indent=4)
    with open('class_indices.json', 'w') as json_file:
        json_file.write(json_str)
    batch_size = 24
    nw = min([os.cpu_count(), batch_size if batch_size > 1 else 0, 8])
    print('Using {} dataloader workers every process'.format(nw))
    train_loader = torch.utils.data.DataLoader(train_dataset, batch_size=batch_size, shuffle=True,
                                               num_workers=nw)

    validate_dataset = datasets.ImageFolder(root=os.path.join(image_path, "val"),
                                            transform=data_transform["val"])
    val_num = len(validate_dataset)
    validate_loader = torch.utils.data.DataLoader(validate_dataset, batch_size=batch_size, shuffle=False,
                                                  num_workers=nw)
    print("using {} images for training, {} images for validation.".format(train_num, val_num))
    model_name = "vgg16"
    net = vgg(model_name=model_name, num_classes=5, init_weights=True)
    net.to(device)
    loss_function = nn.CrossEntropyLoss()
    optimizer = optim.Adam(net.parameters(), lr=0.0001)
    print(train_dataset[0][0].shape)
    print(train_dataset[0])
    epochs = 1
    best_acc = 0.0
    save_path = 'save_pth/{}Net.pth'.format(model_name)
    train_steps = len(train_loader)
    for epoch in range(epochs):
        net.train()
        running_loss = 0.0
        train_bar = tqdm(train_loader)
        for step, data in enumerate(train_bar):
            images, labels = data
            optimizer.zero_grad()
            outputs = net(images.to(device))
            loss = loss_function(outputs, labels.to(device))
            loss.backward()
            optimizer.step()
            running_loss += loss.item()
            train_bar.desc = "train epoch[{}/{}] loss:{:.3f}".format(epoch + 1, epochs, loss)


        net.eval()
        acc = 0.0
        with torch.no_grad():
            val_bar = tqdm(validate_loader)
            for val_data in val_bar:
                val_images, val_labels = val_data
                outputs = net(val_images.to(device))
                predict_y = torch.max(outputs, dim=1)[1]
                acc += torch.eq(predict_y, val_labels.to(device)).sum().item()

        val_accurate = acc / val_num
        print('[epoch %d] train_loss: %.3f  val_accuracy: %.3f' % (epoch + 1, running_loss / train_steps, val_accurate))

        if val_accurate > best_acc:
            best_acc = val_accurate
            torch.save(net.state_dict(), save_path)

    print('Finished Training')


if __name__ == '__main__':
    main()

predict.py

from model import vgg


def main():

    # device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
    device = torch.device("cpu")
    data_transform = transforms.Compose(
        [
            transforms.Resize((224, 224)),
            transforms.ToTensor(),
            transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))
        ]
    )
    img_path = "./tulip.jpg"
    assert os.path.exists(img_path), "file {} does not exist.".format(img_path)

    img = Image.open(img_path)
    plt.imshow(img)

    img = data_transform(img)
    img = torch.unsqueeze(img, dim=0)

    json_path = './class_indices.json'
    assert os.path.exists(json_path), "file {} does not exist.".format(json_path)
    json_file = open(json_path, "r")
    class_indict = json.load(json_file)
    model = vgg(model_name="vgg16", num_classes=5).to(device)
    weights_path = 'save_pth/vgg16Net.pth'
    assert os.path.exists(weights_path), "file {} does not exist.".format(weights_path)
    model.load_state_dict(torch.load(weights_path, map_location=device))
    model.eval()
    with torch.no_grad():
        output = torch.squeeze(model(img.to(device))).cpu()
        predict = torch.softmax(output, dim=0)
        predict_cla = torch.argmax(predict).numpy()

    print_res = "class : {}  prob : {:.3}".format(class_indict[str(predict_cla)],
                                                  predict[predict_cla].numpy())
    plt.title(print_res)
    print(print_res)
    plt.show()


if __name__ == "__main__":
    main()

paddle

import json

import paddle
import paddle.nn as nn
import paddle.vision as torchvision
from paddle.vision import transforms, datasets
import paddle.optimizer as optim
from tqdm import tqdm
import paddle.fluid as fluid
import numpy as np
class VGG(nn.Layer):
    def __init__(self, features, num_classes=1000):
        super(VGG, self).__init__()
        weight_attr = paddle.framework.ParamAttr(initializer=paddle.nn.initializer.XavierNormal())
        bias_attr = paddle.framework.ParamAttr(initializer=paddle.nn.initializer.Constant(0))
        self.features = features
        self.classifier = nn.Sequential(
            nn.Linear(512*7*7, 4096, weight_attr=weight_attr, bias_attr=bias_attr),
            nn.ReLU(),
            nn.Dropout(p=0.5),
            nn.Linear(4096, 4096, weight_attr=weight_attr, bias_attr=bias_attr),
            nn.ReLU(),
            nn.Dropout(p=0.5),
            nn.Linear(4096, num_classes, weight_attr=weight_attr, bias_attr=bias_attr),
        )

    def forward(self, x):
        x = self.features(x)
        x = paddle.flatten(x, start_axis=1)
        x = self.classifier(x)
        return x


def make_features(cfg: list):
    layer = []
    in_channels = 3
    weight_attr = paddle.framework.ParamAttr(initializer=paddle.nn.initializer.XavierNormal())
    bias_attr = paddle.framework.ParamAttr(initializer=paddle.nn.initializer.Constant(0))
    for v in cfg:
        if v == 'M':
            layer += [nn.MaxPool2D(kernel_size=2, stride=2)]
        else:
            conv2d = nn.Conv2D(in_channels, v, kernel_size=3, padding=1, weight_attr=weight_attr, bias_attr=bias_attr)
            layer += [conv2d, nn.ReLU()]
            in_channels = v
    return nn.Sequential(*layer)  # 非关键字参数


cfgs = {
    'vgg11': [64, 'M', 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
    'vgg13': [64, 64, 'M', 128, 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
    'vgg16': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 'M', 512, 512, 512, 'M', 512, 512, 512, 'M'],
    'vgg19': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 256, 'M', 512, 512, 512, 512, 'M', 512, 512, 512, 512, 'M'],
}


def vgg(model_name="vgg16", **kwargs):
    assert model_name in cfgs, "Warning: model number {} not in cfgs dict!".format(model_name)
    cfg = cfgs[model_name]
    model = VGG(make_features(cfg), **kwargs)
    return model
net_test = vgg(model_name="vgg16", num_classes=5)
print(net_test)
print("--------------------------------------------------------")
print("named_parameters():")
for name, parameter in net_test.named_parameters():
    print(name, type(parameter), parameter.shape,parameter.dtype)
    # print(parameter)
# print("--------------------------------------------------------")
# print("sublayers():")
# for m in net_test.sublayers():
#     print(m)
def train_main():
    is_available = len(paddle.static.cuda_places()) > 0
    device = 'gpu:0' if is_available else 'cpu'
    print("using {} device.".format(device))

    data_transform = {
        'train': transforms.Compose(
            [
                transforms.RandomResizedCrop(224),
                transforms.RandomHorizontalFlip(),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
            ]
        ),
        'val': transforms.Compose(
            [
                transforms.Resize((224, 224)),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
            ]
        )
    }

    
    image_path = os.path.join(os.path.join(os.getcwd(), 'work', 'flower_data'))
    assert os.path.exists(image_path), "{} path does not exist.".format(image_path)
    train_dataset = datasets.DatasetFolder(root=os.path.join(image_path, "train"),
                                           transform=data_transform["train"])

    train_num = len(train_dataset)

    flower_list = train_dataset.class_to_idx
    # print(flower_list)
    cla_dict = dict((val, key) for key, val in flower_list.items())
    # print(cla_dict)
    json_str = json.dumps(cla_dict, indent=4)
    with open('class_indices.json', 'w') as json_file:
        json_file.write(json_str)
    batch_size = 32
    train_loader = paddle.io.DataLoader(train_dataset, batch_size=batch_size, shuffle=True, num_workers=0)

    
    validate_dataset = datasets.DatasetFolder(root=os.path.join(image_path, "val"), transform=data_transform["val"])
    val_num = len(validate_dataset)
    validate_loader = paddle.io.DataLoader(validate_dataset, batch_size=batch_size, shuffle=True, num_workers=0)
    
    print("using {} images for training, {} images for validation.".format(train_num, val_num))
    model_name = "vgg16"
    net = vgg(model_name=model_name, num_classes=5)
    loss_function = nn.CrossEntropyLoss()
    optimizer = optim.Adam(parameters=net.parameters(), learning_rate=0.0001)

    epochs = 5   # 训练次数
    best_acc = 0.0
    save_path = 'save_pth/{}Net.pth'.format(model_name)
    train_steps = len(train_loader)

    for epoch in range(epochs):
        net.train()
        running_loss = 0.0
        train_bar = tqdm(train_loader)
        for step, data in enumerate(train_bar):
            images, labels = data
            optimizer.clear_grad()
            outputs = net(images)
            loss = loss_function(outputs, labels)
            loss.backward()
            optimizer.step()
            a = loss.numpy()
            running_loss += a.item()
            train_bar.desc = "train epoch[{}/{}] loss:{:.3f}".format(epoch + 1, epochs, a.item())


        net.eval()
        acc = 0.0
        with paddle.no_grad():
            val_bar = tqdm(validate_loader)
            for val_data in val_bar:
                val_images, val_labels = val_data
                # print(val_labels)
                outputs = net(val_images)
                # print(outputs)
                predict_y = paddle.argmax(outputs, axis=1)
                # print(predict_y)
                b = paddle.equal(predict_y, val_labels)
                b = b.numpy()
                b = b.sum()
                acc += b


        val_accurate = acc / val_num
        print('[epoch %d] train_loss: %.3f  val_accuracy: %.3f' % (epoch + 1, running_loss / train_steps, val_accurate))

        if val_accurate > best_acc:
            best_acc = val_accurate
            paddle.save(net.state_dict(), save_path)

    print('Finished Training')
# 训练时间过长,不是每次预测都需要重新训练一下
Train_table = True

if Train_table: 
    use_gpu = True
    place = paddle.CUDAPlace(0) if use_gpu else paddle.CPUPlace()
    with fluid.dygraph.guard(place):
        train_main()
else:
    print("train_pth does exist.")
from PIL import Image
import matplotlib.pyplot as plt
def predict_main():
    dat_transform = transforms.Compose(
        [
            transforms.Resize((224, 224)),
            transforms.ToTensor(),
            transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
        ]
    )
    img_path = './tulip.jpg'
    assert os.path.exists(img_path), "file {} does not exist.".format(img_path)
    img = Image.open(img_path)
    plt.imshow(img)

    img = dat_transform(img)
    img = paddle.unsqueeze(img, axis=0)
    json_path = './class_indices.json'
    assert os.path.exists(json_path), "file {} does not exist.".format(json_path)
    json_file = open(json_path, 'r')
    class_indict = json.load(json_file)
    weights_path = "save_pth/vgg16Net.pth"
    assert os.path.exists(weights_path),"file {} does not exist.".format(weights_path)
    model = vgg(model_name="vgg16", num_classes=5)
    model.set_state_dict(paddle.load(weights_path))
    model.eval()
    with paddle.no_grad():
        output = paddle.squeeze(model(img))
        # print(output)
        predict = paddle.nn.functional.softmax(output)
        predict_cla = paddle.argmax(predict).numpy()
    print(predict)
    # print(int(predict_cla))
    # print(class_indict)
    # print(class_indict[str(int(predict_cla))])
    # print(predict.numpy()[predict_cla].item())
    print_res = "class : {}  prob : {:.3}".format(class_indict[str(int(predict_cla))],predict.numpy()[predict_cla].item())

    plt.title(print_res)
    print(print_res)
    plt.show()

vggnet pytorch_Javaweb项目

vggnet pytorch_Javaweb项目

最后自己选的是个郁金香,说实话自己也看不出来这个像不像玫瑰,但是epochs调大后,VggNet对这幅图更加坚定的认是玫瑰,可能因为它红吧!

版权声明:本文内容由互联网用户自发贡献,该文观点仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请联系我们举报,一经查实,本站将立刻删除。

发布者:全栈程序员-站长,转载请注明出处:https://javaforall.net/210450.html原文链接:https://javaforall.net

(0)
全栈程序员-站长的头像全栈程序员-站长


相关推荐

  • linux mysql数据库备份以及还原[通俗易懂]

    linux mysql数据库备份以及还原[通俗易懂]1备份命令mysqldump-h127.0.0.1-P3306-uroot-p123456databasename>database.sql2数据库还原命令mysql-h127.0.0.1-P3306-uroot-p123456databasename<database.sql

    2022年5月11日
    36
  • mysql数据库视图索引_MySQL数据库的视图、索引「建议收藏」

    mysql数据库视图索引_MySQL数据库的视图、索引「建议收藏」视图:根据某个实表查询出来的结果,而生成的一个虚表。注意:1.视图既然作为一张虚表存在,那么对实表的增删改查操作,视图同样成立。2.视图既然根据实表得到,那对视图的增删改查操作,也会影响实表。3.视图在查询过程中,如果有函数,一定要起别名。语法:1.创建视图createview视图名asselect查询语句;2.修改视图alterview视图名asselect查询语句;3….

    2022年7月22日
    9
  • isalpha()方法可以检测字符串是否全为字母_isalpha()函数是什么意思

    isalpha()方法可以检测字符串是否全为字母_isalpha()函数是什么意思isalpha()方法描述Pythonisalpha()方法检测字符串是否只由字母组成。语法isalpha()方法语法:参数无。无。返回值如果字符串至少有一个字符并且所有字符都是

    2022年8月4日
    2
  • 自学Java开发一般需要多久?

    自学Java开发一般需要多久?自学Java开发一般需要多久?相信有很多想转行或者想学习Java的人都会关注这个问题!那我们今天就来说一下这个问题,具体需要多久呢?这个时间因人而异,毕竟每个人的学习能力和效率都是不同的!打个比方,如果你是零基础,每天学习8小时,基本上每天都按时学习的话,大概需要半年多的时间,就能学的差不多了!如果你本身就会C或C++语言,那么Java对你来说也许会简单许多,学起来自然就快了!下面就给大家简单说一下学习方法,让你尽可能快的学会Java!学习路线:…

    2022年7月8日
    26
  • java拦截器放行_java拦截器放行某些请求

    java拦截器放行_java拦截器放行某些请求在java开发中,拦截器使用是很普遍的,最常用的就是登陆拦截了,然后并不是所有的请求我们都需要拦截,比如index页面的请求我们是不拦截的.通常情况下我们有两种方式:先贴出来springboot使用拦截器的case:1.自定义拦截器,实现HandlerInterceptor,也可以采用继承的方式(HandlerInterceptorAdapter),内容不重要,看过程publicclassL…

    2022年6月7日
    155
  • 关于MSHTML_Html格式

    关于MSHTML_Html格式本文翻译自http://msdn.microsoft.com/workshop/browser/mshtml/overview/overview.aspMSDNHome>MSDNLibra

    2022年8月2日
    3

发表回复

您的邮箱地址不会被公开。 必填项已用 * 标注

关注全栈程序员社区公众号