spring security + oauth2 使用RedisTokenStore 以json格式存储

news2024/11/24 11:51:29

1.项目架构

 2.自己对 TokenStore 的 redis实现

package com.enterprise.auth.config;

import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.Cursor;
import org.springframework.data.redis.core.ScanOptions;
import org.springframework.security.oauth2.common.ExpiringOAuth2RefreshToken;
import org.springframework.security.oauth2.common.OAuth2AccessToken;
import org.springframework.security.oauth2.common.OAuth2RefreshToken;
import org.springframework.security.oauth2.provider.OAuth2Authentication;
import org.springframework.security.oauth2.provider.token.AuthenticationKeyGenerator;
import org.springframework.security.oauth2.provider.token.DefaultAuthenticationKeyGenerator;
import org.springframework.security.oauth2.provider.token.TokenStore;
import org.springframework.security.oauth2.provider.token.store.redis.JdkSerializationStrategy;
import org.springframework.security.oauth2.provider.token.store.redis.RedisTokenStore;
import org.springframework.security.oauth2.provider.token.store.redis.RedisTokenStoreSerializationStrategy;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;

import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
import java.util.*;

public class MyRedisTokenStore implements TokenStore {

    private static final String ACCESS = "access:";
    private static final String AUTH_TO_ACCESS = "auth_to_access:";
    private static final String AUTH = "auth:";
    private static final String REFRESH_AUTH = "refresh_auth:";
    private static final String ACCESS_TO_REFRESH = "access_to_refresh:";
    private static final String REFRESH = "refresh:";
    private static final String REFRESH_TO_ACCESS = "refresh_to_access:";
    private static final String CLIENT_ID_TO_ACCESS = "client_id_to_access:";
    private static final String UNAME_TO_ACCESS = "uname_to_access:";
    private static final boolean springDataRedis_2_0 = ClassUtils.isPresent("org.springframework.data.redis.connection.RedisStandaloneConfiguration", RedisTokenStore.class.getClassLoader());
    private final RedisConnectionFactory connectionFactory;
    private AuthenticationKeyGenerator authenticationKeyGenerator = new DefaultAuthenticationKeyGenerator();
    private RedisTokenStoreSerializationStrategy serializationStrategy = new MyRedisTokenStoreSerializationStrategy();
    private String prefix = "";
    private Method redisConnectionSet_2_0;

    public MyRedisTokenStore(RedisConnectionFactory connectionFactory) {
        this.connectionFactory = connectionFactory;
        if (springDataRedis_2_0) {
            this.loadRedisConnectionMethods_2_0();
        }

    }

    public void setAuthenticationKeyGenerator(AuthenticationKeyGenerator authenticationKeyGenerator) {
        this.authenticationKeyGenerator = authenticationKeyGenerator;
    }

    public void setSerializationStrategy(RedisTokenStoreSerializationStrategy serializationStrategy) {
        this.serializationStrategy = serializationStrategy;
    }

    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }

    private void loadRedisConnectionMethods_2_0() {
        this.redisConnectionSet_2_0 = ReflectionUtils.findMethod(RedisConnection.class, "set", new Class[]{byte[].class, byte[].class});
    }

    private RedisConnection getConnection() {
        return this.connectionFactory.getConnection();
    }

    private byte[] serialize(Object object) {
        return this.serializationStrategy.serialize(object);
    }

    private byte[] serializeKey(String object) {
        return this.serialize(this.prefix + object);
    }

    private OAuth2AccessToken deserializeAccessToken(byte[] bytes) {
        return (OAuth2AccessToken)this.serializationStrategy.deserialize(bytes, OAuth2AccessToken.class);
    }

    private OAuth2Authentication deserializeAuthentication(byte[] bytes) {
        return (OAuth2Authentication)this.serializationStrategy.deserialize(bytes, OAuth2Authentication.class);
    }

    private OAuth2RefreshToken deserializeRefreshToken(byte[] bytes) {
        return (OAuth2RefreshToken)this.serializationStrategy.deserialize(bytes, OAuth2RefreshToken.class);
    }

    private byte[] serialize(String string) {
        return this.serializationStrategy.serialize(string);
    }

    private String deserializeString(byte[] bytes) {
        return this.serializationStrategy.deserializeString(bytes);
    }

    public OAuth2AccessToken getAccessToken(OAuth2Authentication authentication) {
        String key = this.authenticationKeyGenerator.extractKey(authentication);
        byte[] serializedKey = this.serializeKey("auth_to_access:" + key);
        byte[] bytes = null;
        RedisConnection conn = this.getConnection();

        try {
            bytes = conn.get(serializedKey);
        } finally {
            conn.close();
        }

        OAuth2AccessToken accessToken = this.deserializeAccessToken(bytes);
        if (accessToken != null) {
            OAuth2Authentication storedAuthentication = this.readAuthentication(accessToken.getValue());
            if (storedAuthentication == null || !key.equals(this.authenticationKeyGenerator.extractKey(storedAuthentication))) {
                this.storeAccessToken(accessToken, authentication);
            }
        }

        return accessToken;
    }

    public OAuth2Authentication readAuthentication(OAuth2AccessToken token) {
        return this.readAuthentication(token.getValue());
    }

    public OAuth2Authentication readAuthentication(String token) {
        byte[] bytes = null;
        RedisConnection conn = this.getConnection();

        try {
            bytes = conn.get(this.serializeKey("auth:" + token));
        } finally {
            conn.close();
        }

        OAuth2Authentication var4 = this.deserializeAuthentication(bytes);
        return var4;
    }

    public OAuth2Authentication readAuthenticationForRefreshToken(OAuth2RefreshToken token) {
        return this.readAuthenticationForRefreshToken(token.getValue());
    }

    public OAuth2Authentication readAuthenticationForRefreshToken(String token) {
        RedisConnection conn = this.getConnection();

        OAuth2Authentication var5;
        try {
            byte[] bytes = conn.get(this.serializeKey("refresh_auth:" + token));
            OAuth2Authentication auth = this.deserializeAuthentication(bytes);
            var5 = auth;
        } finally {
            conn.close();
        }

        return var5;
    }

    public void storeAccessToken(OAuth2AccessToken token, OAuth2Authentication authentication) {
        byte[] serializedAccessToken = this.serialize((Object)token);
        byte[] serializedAuth = this.serialize((Object)authentication);
        byte[] accessKey = this.serializeKey("access:" + token.getValue());
        byte[] authKey = this.serializeKey("auth:" + token.getValue());
        byte[] authToAccessKey = this.serializeKey("auth_to_access:" + this.authenticationKeyGenerator.extractKey(authentication));
        byte[] approvalKey = this.serializeKey("uname_to_access:" + getApprovalKey(authentication));
        byte[] clientId = this.serializeKey("client_id_to_access:" + authentication.getOAuth2Request().getClientId());
        RedisConnection conn = this.getConnection();

        try {
            conn.openPipeline();
            if (springDataRedis_2_0) {
                try {
                    this.redisConnectionSet_2_0.invoke(conn, accessKey, serializedAccessToken);
                    this.redisConnectionSet_2_0.invoke(conn, authKey, serializedAuth);
                    this.redisConnectionSet_2_0.invoke(conn, authToAccessKey, serializedAccessToken);
                } catch (Exception var24) {
                    throw new RuntimeException(var24);
                }
            } else {
                conn.set(accessKey, serializedAccessToken);
                conn.set(authKey, serializedAuth);
                conn.set(authToAccessKey, serializedAccessToken);
            }

            if (!authentication.isClientOnly()) {
                conn.sAdd(approvalKey, new byte[][]{serializedAccessToken});
            }

            conn.sAdd(clientId, new byte[][]{serializedAccessToken});
            if (token.getExpiration() != null) {
                int seconds = token.getExpiresIn();
                conn.expire(accessKey, (long)seconds);
                conn.expire(authKey, (long)seconds);
                conn.expire(authToAccessKey, (long)seconds);
                conn.expire(clientId, (long)seconds);
                conn.expire(approvalKey, (long)seconds);
            }

            OAuth2RefreshToken refreshToken = token.getRefreshToken();
            if (refreshToken != null && refreshToken.getValue() != null) {
                byte[] refresh = this.serialize(token.getRefreshToken().getValue());
                byte[] auth = this.serialize(token.getValue());
                byte[] refreshToAccessKey = this.serializeKey("refresh_to_access:" + token.getRefreshToken().getValue());
                byte[] accessToRefreshKey = this.serializeKey("access_to_refresh:" + token.getValue());
                if (springDataRedis_2_0) {
                    try {
                        this.redisConnectionSet_2_0.invoke(conn, refreshToAccessKey, auth);
                        this.redisConnectionSet_2_0.invoke(conn, accessToRefreshKey, refresh);
                    } catch (Exception var23) {
                        throw new RuntimeException(var23);
                    }
                } else {
                    conn.set(refreshToAccessKey, auth);
                    conn.set(accessToRefreshKey, refresh);
                }

                if (refreshToken instanceof ExpiringOAuth2RefreshToken) {
                    ExpiringOAuth2RefreshToken expiringRefreshToken = (ExpiringOAuth2RefreshToken)refreshToken;
                    Date expiration = expiringRefreshToken.getExpiration();
                    if (expiration != null) {
                        int seconds = Long.valueOf((expiration.getTime() - System.currentTimeMillis()) / 1000L).intValue();
                        conn.expire(refreshToAccessKey, (long)seconds);
                        conn.expire(accessToRefreshKey, (long)seconds);
                    }
                }
            }

            conn.closePipeline();
        } finally {
            conn.close();
        }

    }

    private static String getApprovalKey(OAuth2Authentication authentication) {
        String userName = authentication.getUserAuthentication() == null ? "" : authentication.getUserAuthentication().getName();
        return getApprovalKey(authentication.getOAuth2Request().getClientId(), userName);
    }

    private static String getApprovalKey(String clientId, String userName) {
        return clientId + (userName == null ? "" : ":" + userName);
    }

    public void removeAccessToken(OAuth2AccessToken accessToken) {
        this.removeAccessToken(accessToken.getValue());
    }

    public OAuth2AccessToken readAccessToken(String tokenValue) {
        byte[] key = this.serializeKey("access:" + tokenValue);
        byte[] bytes = null;
        RedisConnection conn = this.getConnection();

        try {
            bytes = conn.get(key);
        } finally {
            conn.close();
        }

        OAuth2AccessToken var5 = this.deserializeAccessToken(bytes);
        return var5;
    }

    public void removeAccessToken(String tokenValue) {
        byte[] accessKey = this.serializeKey("access:" + tokenValue);
        byte[] authKey = this.serializeKey("auth:" + tokenValue);
        byte[] accessToRefreshKey = this.serializeKey("access_to_refresh:" + tokenValue);
        RedisConnection conn = this.getConnection();

        try {
            conn.openPipeline();
            conn.get(accessKey);
            conn.get(authKey);
            conn.del(new byte[][]{accessKey});
            conn.del(new byte[][]{accessToRefreshKey});
            conn.del(new byte[][]{authKey});
            List<Object> results = conn.closePipeline();
            byte[] access = (byte[])((byte[])results.get(0));
            byte[] auth = (byte[])((byte[])results.get(1));
            OAuth2Authentication authentication = this.deserializeAuthentication(auth);
            if (authentication != null) {
                String key = this.authenticationKeyGenerator.extractKey(authentication);
                byte[] authToAccessKey = this.serializeKey("auth_to_access:" + key);
                byte[] unameKey = this.serializeKey("uname_to_access:" + getApprovalKey(authentication));
                byte[] clientId = this.serializeKey("client_id_to_access:" + authentication.getOAuth2Request().getClientId());
                conn.openPipeline();
                conn.del(new byte[][]{authToAccessKey});
                conn.sRem(unameKey, new byte[][]{access});
                conn.sRem(clientId, new byte[][]{access});
                conn.del(new byte[][]{this.serialize("access:" + key)});
                conn.closePipeline();
            }
        } finally {
            conn.close();
        }

    }

    public void storeRefreshToken(OAuth2RefreshToken refreshToken, OAuth2Authentication authentication) {
        byte[] refreshKey = this.serializeKey("refresh:" + refreshToken.getValue());
        byte[] refreshAuthKey = this.serializeKey("refresh_auth:" + refreshToken.getValue());
        byte[] serializedRefreshToken = this.serialize((Object)refreshToken);
        RedisConnection conn = this.getConnection();

        try {
            conn.openPipeline();
            if (springDataRedis_2_0) {
                try {
                    this.redisConnectionSet_2_0.invoke(conn, refreshKey, serializedRefreshToken);
                    this.redisConnectionSet_2_0.invoke(conn, refreshAuthKey, this.serialize((Object)authentication));
                } catch (Exception var13) {
                    throw new RuntimeException(var13);
                }
            } else {
                conn.set(refreshKey, serializedRefreshToken);
                conn.set(refreshAuthKey, this.serialize((Object)authentication));
            }

            if (refreshToken instanceof ExpiringOAuth2RefreshToken) {
                ExpiringOAuth2RefreshToken expiringRefreshToken = (ExpiringOAuth2RefreshToken)refreshToken;
                Date expiration = expiringRefreshToken.getExpiration();
                if (expiration != null) {
                    int seconds = Long.valueOf((expiration.getTime() - System.currentTimeMillis()) / 1000L).intValue();
                    conn.expire(refreshKey, (long)seconds);
                    conn.expire(refreshAuthKey, (long)seconds);
                }
            }

            conn.closePipeline();
        } finally {
            conn.close();
        }

    }

    public OAuth2RefreshToken readRefreshToken(String tokenValue) {
        byte[] key = this.serializeKey("refresh:" + tokenValue);
        byte[] bytes = null;
        RedisConnection conn = this.getConnection();

        try {
            bytes = conn.get(key);
        } finally {
            conn.close();
        }

        OAuth2RefreshToken var5 = this.deserializeRefreshToken(bytes);
        return var5;
    }

    public void removeRefreshToken(OAuth2RefreshToken refreshToken) {
        this.removeRefreshToken(refreshToken.getValue());
    }

    public void removeRefreshToken(String tokenValue) {
        byte[] refreshKey = this.serializeKey("refresh:" + tokenValue);
        byte[] refreshAuthKey = this.serializeKey("refresh_auth:" + tokenValue);
        byte[] refresh2AccessKey = this.serializeKey("refresh_to_access:" + tokenValue);
        byte[] access2RefreshKey = this.serializeKey("access_to_refresh:" + tokenValue);
        RedisConnection conn = this.getConnection();

        try {
            conn.openPipeline();
            conn.del(new byte[][]{refreshKey});
            conn.del(new byte[][]{refreshAuthKey});
            conn.del(new byte[][]{refresh2AccessKey});
            conn.del(new byte[][]{access2RefreshKey});
            conn.closePipeline();
        } finally {
            conn.close();
        }

    }

    public void removeAccessTokenUsingRefreshToken(OAuth2RefreshToken refreshToken) {
        this.removeAccessTokenUsingRefreshToken(refreshToken.getValue());
    }

    private void removeAccessTokenUsingRefreshToken(String refreshToken) {
        byte[] key = this.serializeKey("refresh_to_access:" + refreshToken);
        List<Object> results = null;
        RedisConnection conn = this.getConnection();

        try {
            conn.openPipeline();
            conn.get(key);
            conn.del(new byte[][]{key});
            results = conn.closePipeline();
        } finally {
            conn.close();
        }

        if (results != null) {
            byte[] bytes = (byte[])((byte[])results.get(0));
            String accessToken = this.deserializeString(bytes);
            if (accessToken != null) {
                this.removeAccessToken(accessToken);
            }

        }
    }

    private List<byte[]> getByteLists(byte[] approvalKey, RedisConnection conn) {
        Long size = conn.sCard(approvalKey);
        List<byte[]> byteList = new ArrayList(size.intValue());
        Cursor cursor = conn.sScan(approvalKey, ScanOptions.NONE);

        while(cursor.hasNext()) {
            Object next = cursor.next();
            byteList.add(next.toString().getBytes(StandardCharsets.UTF_8));
        }

        return byteList;
    }

    public Collection<OAuth2AccessToken> findTokensByClientIdAndUserName(String clientId, String userName) {
        byte[] approvalKey = this.serializeKey("uname_to_access:" + getApprovalKey(clientId, userName));
        List<byte[]> byteList = null;
        RedisConnection conn = this.getConnection();

        try {
            byteList = this.getByteLists(approvalKey, conn);
        } finally {
            conn.close();
        }

        if (byteList != null && byteList.size() != 0) {
            List<OAuth2AccessToken> accessTokens = new ArrayList(byteList.size());
            Iterator var7 = byteList.iterator();

            while(var7.hasNext()) {
                byte[] bytes = (byte[])var7.next();
                OAuth2AccessToken accessToken = this.deserializeAccessToken(bytes);
                accessTokens.add(accessToken);
            }

            return Collections.unmodifiableCollection(accessTokens);
        } else {
            return Collections.emptySet();
        }
    }

    public Collection<OAuth2AccessToken> findTokensByClientId(String clientId) {
        byte[] key = this.serializeKey("client_id_to_access:" + clientId);
        List<byte[]> byteList = null;
        RedisConnection conn = this.getConnection();

        try {
            byteList = this.getByteLists(key, conn);
        } finally {
            conn.close();
        }

        if (byteList != null && byteList.size() != 0) {
            List<OAuth2AccessToken> accessTokens = new ArrayList(byteList.size());
            Iterator var6 = byteList.iterator();

            while(var6.hasNext()) {
                byte[] bytes = (byte[])var6.next();
                OAuth2AccessToken accessToken = this.deserializeAccessToken(bytes);
                accessTokens.add(accessToken);
            }

            return Collections.unmodifiableCollection(accessTokens);
        } else {
            return Collections.emptySet();
        }
    }
}

3.自定义序列化类

package com.enterprise.auth.config;

import com.google.gson.Gson;
import org.springframework.security.oauth2.provider.token.store.redis.BaseRedisTokenStoreSerializationStrategy;

import java.nio.charset.StandardCharsets;
import java.util.Map;

public class MyRedisTokenStoreSerializationStrategy extends BaseRedisTokenStoreSerializationStrategy {
    @Override
    //反序列化内部
    protected <T> T deserializeInternal(byte[] bytes, Class<T> aClass) {
        String s = new String(bytes);
        Gson gson = new Gson();
        return gson.fromJson(s,aClass);
    }

    @Override
    //反序列化字符串内部
    protected String deserializeStringInternal(byte[] bytes) {
        return new String(bytes);
    }

    @Override
    //序列化内部
    protected byte[] serializeInternal(Object o) {
        Gson gson = new Gson();
        String json = gson.toJson(o);
        return json.getBytes(StandardCharsets.UTF_8);
    }

    @Override
    //序列化内部
    protected byte[] serializeInternal(String s) {
        return  s.getBytes(StandardCharsets.UTF_8);
    }
}

4.配置使用redis类型的 TokenStore

package com.enterprise.auth.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.security.oauth2.provider.token.TokenStore;

@Configuration
public class MyRedisTokenStoreConfig {
    @Autowired
    private RedisConnectionFactory redisConnectionFactory;
    @Bean
    public TokenStore tokenStore() {
        MyRedisTokenStore redisTokenStore = new MyRedisTokenStore(redisConnectionFactory);
        return redisTokenStore;
    }
}

5.完成认证模块的编写后,测试登录

 

 json已经保存在数据库了

但是!!!!!,保存没问题,取出来的时候就有问题了,把这三个文件复制到资源服务器,让资源服务器也用MyRedisTokenStore 的方式读取权限信息.

 然后访问,到json权限信息转成实体类的时候,就有问题了,各种各样oauth2 中的数据实体类,没有构造方法,无法创建对象,先转成map在手动新建对象同样不行,

 redis中的配置已经读到了

 但是需要实例化的对象类路径,这么长一串,没有构造方法,无法新建对象.

报错>>>

 

结束<<<<<<<<

本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。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。如若转载，请注明出处：http://www.coloradmin.cn/o/840712.html

如若内容造成侵权/违法违规/事实不符，请联系多彩编程网进行投诉反馈，一经查实，立即删除！

相关文章

leetcode刷题:1657. 确定两个字符串是否接近、1004. 最大连续1的个数 III

leetcode刷题:1657. 确定两个字符串是否接近、1004. 最大连续1的个数 III

leetcode刷题:1657. 确定两个字符串是否接近、1004. 最大连续1的个数 III 1. 前言2. 1657. 确定两个字符串是否接近3. 1004. 最大连续1的个数 III4. 总结 1. 前言 上述两个题目位于leetcode75中&#xff0c;难度为中等&#xff0c;虽然对于大佬而言&#xff0c;可能很简单&…
阅读更多...
2023年C++面试宝典

2023年C++面试宝典

目录 第一章&#xff1a;C基础知识1.1 C语言起源与发展1.2 C的重要特点和优点1.3 C的数据类型和变量1.4 函数和命名空间1.5 运算符和表达式 第二章&#xff1a;面向对象编程2.1 类与对象的概念2.2 封装、继承和多态2.3 构造函数和析构函数2.4 静态成员和常量成员2.5 虚函数和纯…
阅读更多...
maven install命令：将包安装在本地仓库，供本地的其它工程或者模块依赖

maven install命令：将包安装在本地仓库，供本地的其它工程或者模块依赖

说明 有时候&#xff0c;自己本地的maven工程依赖于本地的其它工程&#xff0c;或者manven工程中的一个模块依赖于另外的模块&#xff0c;可以执行maven的install命令&#xff0c;将被依赖的包安装在maven本地仓库。 示例 一个工程包含几个模块&#xff0c;模块之间存在依赖…
阅读更多...
【笔记】第94期-冯永吉-《湖仓集一体关键技术解读》-大数据百家讲坛-厦大数据库实验室主办20221022

【笔记】第94期-冯永吉-《湖仓集一体关键技术解读》-大数据百家讲坛-厦大数据库实验室主办20221022

https://www.bilibili.com/video/BV1714y1j7AU/?spm_id_from333.337.search-card.all.click&vd_sourcefa36a95b3c3fa4f32dd400f8cabddeaf
阅读更多...
VSCode配置SSH远程免密登录服务器

VSCode配置SSH远程免密登录服务器

VScode远程开发时&#xff0c;每次都需要输入密码&#xff0c;其实同理可以和其他应用类似配置免密登录&#xff0c;流程也类似。 1.在本地主机生成公钥和秘钥 ssh-keygen 2.将公钥内容添加至服务器 将生成钥对时会给出其保存路径&#xff0c;找到公钥&#xff0c;复制内容&am…
阅读更多...
废弃的 电信光猫 改为 免费的wifi

废弃的 电信光猫 改为 免费的wifi

修改为桥接模式即可。 1.修改电脑IP地址与光猫同一网段&#xff0c;例如192.168.1.2 掩码255.255.255.0。 电信光猫默认地址为 192.168.1.1 掩码为 255.255.255.0 2.网线或者无线连接光猫&#xff0c;无线wifi 名称&#xff08;SSID&#xff09;和密码 光猫背后都有。 3.浏…
阅读更多...
事务到底是隔离的还是不隔离的 （具体）

事务到底是隔离的还是不隔离的 （具体）

遇到不明白的慢慢往后读&#xff0c;一下你就明白了。 下面是一个只有两行的表的初始化语句 mysql> CREATE TABLE t ( id int(11) NOT NULL, k int(11) DEFAULT NULL, PRIMARY KEY (id) ) ENGINEInnoDB; insert into t(id, k) values(1,1),(2,2); 这里&#xff0c;我们需要注…
阅读更多...
ADS版图画封装联合仿真学习视频

ADS版图画封装联合仿真学习视频

ADS版图画封装 因为晶体管ATF54143在ADS中是没有封装的&#xff0c;所以要在ADS中画ATF54143的封装&#xff0c;操作步骤如下&#xff1a; 在ADS中新建layout&#xff0c;命名为ATF54143_layout&#xff0c; 根据datasheet知道封装的大小&#xff0c;进行绘制 在layout的con…
阅读更多...
GO语言基础语法探究：简洁高效的编程之道

GO语言基础语法探究：简洁高效的编程之道

文章目录 前言Go词法单元token标识符关键字&#xff08; 25个 &#xff09;内置数据类型标识符&#xff08; 20个 &#xff09;内置函数&#xff08; 15个 &#xff09;常量值标识符&#xff08; 4个&#xff09;空白标识符&#xff08; 1个 &#xff09; 操作符和分隔符字面常…
阅读更多...
通向架构师的道路之基于数据库的权限系统的设计

通向架构师的道路之基于数据库的权限系统的设计

一、权限系统 这一天将讲述一个基本的基于数据库的权限管理系统的设计&#xff0c;在这一天的课程的最后将讲述“左右值无限分类实现算法”如何来优化“系统菜单”的结构而告终。今天的内容和前几天的基础框架是一样的它们都属于基础知识&#xff0c;在这些基础知识上还可以扩…
阅读更多...
Leetcode 剑指 Offer II 038. 每日温度

Leetcode 剑指 Offer II 038. 每日温度

题目难度: 中等 原题链接 今天继续更新 Leetcode 的剑指 Offer&#xff08;专项突击版&#xff09;系列, 大家在公众号 算法精选 里回复 剑指offer2 就能看到该系列当前连载的所有文章了, 记得关注哦~ 题目描述 请根据每日 气温 列表 temperatures &#xff0c;重新生成一个列…
阅读更多...
第5集丨Vue 江湖 —— 监视属性/侦听属性

第5集丨Vue 江湖 —— 监视属性/侦听属性

目录 一、基本使用1.1 watch配置监视1.2 vm.$watch动态监视1.3 深度监视(deep watch)1.4 简写形式 二、computed和watch的对比2.1 使用watch实现setTimeout操作2.2 用computed无法实现setTimeout 三、其他注意事项3.1 vue devtools的bug3.2 xxxyyy格式3.3 将window传入data中 V…
阅读更多...
高并发负载均衡---LVS

高并发负载均衡---LVS

目录 前言 一&#xff1a;负载均衡概述 二&#xff1a;为啥负载均衡服务器这么快呢&#xff1f; ​编辑 2.1 七层应用程序慢的原因 2.2 四层负载均衡器LVS快的原因 三&#xff1a;LVS负载均衡器的三种模式 3.1 NAT模式 3.1.1 什么是NAT模式 3.1.2 NAT模式实现LVS的缺点…
阅读更多...
c++--二叉树应用

c++--二叉树应用

1.根据二叉树创建字符串 力扣 给你二叉树的根节点 root &#xff0c;请你采用前序遍历的方式&#xff0c;将二叉树转化为一个由括号和整数组成的字符串&#xff0c;返回构造出的字符串。 空节点使用一对空括号对 "()" 表示&#xff0c;转化后需要省略所有不影响字符…
阅读更多...
【react】react中BrowserRouter和HashRouter的区别：

【react】react中BrowserRouter和HashRouter的区别：

文章目录 1.底层原理不一样:2.path衣现形式不一样3.刷新后对路山state参数的影响4.备注: HashRouter可以用于解决一些路径错误相关的问题 1.底层原理不一样: BrowserRouter使用的是H5的history API&#xff0c;不兼容IE9及以下版不。 HashRouter使用的是URL的哈希值。 2.path衣…
阅读更多...
Element-ui中分页器的使用

Element-ui中分页器的使用

<template>中写&#xff1a; js中写&#xff1a;
阅读更多...
pytorch的CrossEntropyLoss交叉熵损失函数默认reduction是平均值

pytorch的CrossEntropyLoss交叉熵损失函数默认reduction是平均值

pytorch中使用nn.CrossEntropyLoss()创建出来的交叉熵损失函数计算损失默认是求平均值的&#xff0c;即多个样本输入后获取的是一个均值标量&#xff0c;而不是样本大小的向量。 net nn.Linear(4, 2) loss nn.CrossEntropyLoss() X torch.rand(10, 4) y torch.ones(10, dt…
阅读更多...
认识 MyBatis + MyBatis如何使用 （MyBatis操作数据库）

认识 MyBatis + MyBatis如何使用 （MyBatis操作数据库）

前言 本篇介绍了什么是MyBatis&#xff0c;MyBatis的前期配置&#xff0c;MyBatis操作数据库的两种方式&#xff1a;.xml文件 / 注释&#xff0c;使用MyBatis的一些注意&#xff0c;如有错误&#xff0c;请在评论区指正&#xff0c;让我们一起交流&#xff0c;共同进步&#x…
阅读更多...
AI 一键去水印：教你无限量使用商业图片的技巧

AI 一键去水印：教你无限量使用商业图片的技巧

场景再现 刚开始注册账号(啥账号具体不表了&#xff0c;小编不喜欢的那个)&#xff0c;想弄个闪亮&#xff0c;好看&#xff0c;有个性化的 Logo。作为一名非专美工小白人员&#xff0c;网上翻了很久作图工具&#xff0c;要么就是不好用&#xff0c;好用的大部分都收费。最后没…
阅读更多...
如何从零开始配置前端环境以及安装必备的软件插件

如何从零开始配置前端环境以及安装必备的软件插件

文章目录 前言一、VSCode&#xff08;Visual Studio Code&#xff09;1.1 VSCode介绍与安装1.2 VSCode 常用插件安装1.3 VSCode代码格式化 二、Node.js2.1 Node的介绍与安装2. yarn的安装 三、Webpcak3.1 Webpcak的介绍与安装 四、Vue CLI4.1 Vue CLI的安装与介绍 五、初始化Vu…
阅读更多...
推荐文章
最新文章

Copyright @ 2022~2023