理论上 UTF-8 使用1~6个字节进行存储，但比较新的 UTF-8 规范只使用 1～4 个字节

**基本多文平面（BMP）**： 三个字节的 UTF-8 最大能编码的 Unicode 字符是 0xFFFF，也就是 Unicode 中的基本多文平面（BMP）。也就是说，任何不在基本多文平面的 Unicode字符，都无法用三字节编码存储。

**不在 BMP 中的字符**： Emoji 表情（Emoji 是一种特殊的 Unicode 编码，常见于 ios 和 android 手机上）、不常用的汉字、新增的 Unicode 字符等等。

**utf8**： 等同于utf8mb3，低版本mysql的默认存储格式，最大字符长度为 3 字节，如果遇到 4 字节的字符就会出现错误了。如上述的Emoji表情

**utf8mb4**： MySQL在5.5.3版本之后增加了这个utf8mb4的编码，mb4就是most bytes 4的意思，专门用来兼容四字节的unicode。其实，utf8mb4是utf8的超集，原来使用utf8，然后将字符集修改为utf8mb4，也会不会对已有的 utf8 编码读取产生任何问题。

可以用 alter 命令解决：

```sql
# 修改相应表
ALTER TABLE logtest CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
# 设置默认编码
ALTER TABLE logtest DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
# 只修改部分字段编码
ALTER TABLE logtest CHANGE title title VARCHAR(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
```

如果还是报错，可以修改数据库编码方式：

```sql
# 查看编码
show variables like '%char%';

# set names进行设置改变三个参数
# character_set_client
# character_set_connection
# character_set_results
set names utf8mb4;

# 或者使用下面命令一个一个更改
set character_set_client = 'utf8mb4';
set character_set_connection = 'utf8mb4';
set character_set_databse = 'utf8mb4';
set character_set_results = 'utf8mb4';
```

其中 `character_set_server` 无法通过命令修改，需要修改 mysql 配置文件，然后重启 mysql 才能生效。

 :grin: 以前记录的笔记，抄给你

小白问题～mysql 默认编码只支持 BMP（基本多文平面）不包含 emoji 等特殊字符，也就是 utf8mb3，你查下命令，数据库编码改为 utf8mb4 就可以了

用户输入 emoji 表情时后端就报错：

> Cause: java.sql.SQLException: Incorrect string value: '' for column 'content' at row 1

啥原因呢？求解。。。

Mysql 字符串编码报错求助：Incorrect string value

同理，flutter reactNative 也是一样的

devcontainer.json

```yaml
// For format details, see https://aka.ms/devcontainer.json. For config options, see the
// README at: https://github.com/devcontainers/templates/tree/main/src/ubuntu
{
	"name": "Fei-Dev",
	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
	"dockerComposeFile": "../docker-dev-build/docker-compose.yml",
	"service": "devcontainer",
	"workspaceFolder": "/workspace",
	"features": {
		"ghcr.io/devcontainers/features/java:1": {},
		"ghcr.io/nordcominc/devcontainer-features/android-sdk:1": {}
	},
	"customizations": {
		"vscode": {
			"extensions": [
				"DavidAnson.vscode-markdownlint",
				"isudox.vscode-jetbrains-keybindings",
				"vscjava.vscode-gradle",
				"totalcross.android-xml-editor",
				"ms-azuretools.vscode-docker",
				"adelphes.android-dev-ext",
				"fwcd.kotlin"
			]
		}
	},
	"shutdownAction": "stopCompose",

	// Use 'forwardPorts' to make a list of ports inside the container available locally.
	// "forwardPorts": [],
	// Use 'postCreateCommand' to run commands after the container is created.
	"postCreateCommand": "adb start-server && sh gradlew build",
	// "postAttachCommand": "adb connect emulator:5555"
	// Configure tool-specific properties.
	// "customizations": {},
	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
	//fixme 尝试使用vscode 用户可以访问volume
	"remoteUser": "root"
}
```

docker-compose.yml

```
services:
  devcontainer:
    image: mcr.microsoft.com/devcontainers/base:ubuntu
    command: /bin/sh -c "while sleep 1000; do :; done"
    ports: 
      - "8080-8090"
    volumes:
      - ..:/workspace:cached
      - gradle-cache:/root/.gradle
      - top-cache:/root/.cache

  emulator:
    image: budtmo/docker-android:emulator_11.0
    ports:
      - "6080"
    environment:
      - EMULATOR_DEVICE=Samsung Galaxy S10
      - WEB_VNC=true
    devices:
      - /dev/kvm

volumes:
  gradle-cache:
  top-cache:
```



分享在docker 里面开发Android 项目

有谁会写毕设

标识符

483DAB9E-B587-4DAE-936C-201F5BC4BCBA

备注

Error Domain=kCFStreamErrorDomainSSL Code=-9806"(null)" UserInfo=/NSLocalizedRecoverySuggestion=Errorcode definition can be found in Apple's SecureTransport.h}

请求信息

CONNECT m.m******(手动打码).pt:443 HTTP/1.1

请求头部

Host: m.m*******.ptConnection: keep-alive

发送请求头部

未发送

服务端开始响应

未响应

请求完成2024/04/26 10:11:40.529

 app无法登录，抓包数据。网页版可以登录，求分析求解

前些天一直在找便宜的云服务器，偶然间发现一免费的云平台，这里推荐给大家。

就是阿贝云，网站是https://www.abeiyun.com

说一下感受

1、阿贝云虽然是一小众的云平台，重在免费，该有的东西都有，还能免备案这是最舒服的。

2、使用了一天，上了项目，网速不慢。

3、唯一要指出来就是磁盘太小。

分享免费云服务器

拉取了rustbuster的v3.0.3版本文件, 二进制文件无法使用, 执行结果如下:

```bash
[root_cn@archlinux target]$ ./rustbuster-v3.0.3-x86_64-unknown-linux-gnu
./rustbuster-v3.0.3-x86_64-unknown-linux-gnu: error while loading shared libraries: libssl.so.1.1: cannot open shared object file: No such file or directory
```

拉取了main源码, 想自行尝试编译, 然后卡在了openssl, 以下为报错信息:

```rust
The following warnings were emitted during compilation:

warning: openssl-sys@0.9.47: build/expando.c:4:24: error: pasting "RUST_VERSION_OPENSSL_" and "(" does not give a valid preprocessing token
warning: openssl-sys@0.9.47:     4 | #define VERSION2(n, v) RUST_VERSION_##n##_##v
warning: openssl-sys@0.9.47:       |                        ^~~~~~~~~~~~~
warning: openssl-sys@0.9.47: build/expando.c:5:23: note: in expansion of macro ‘VERSION2’
warning: openssl-sys@0.9.47:     5 | #define VERSION(n, v) VERSION2(n, v)
warning: openssl-sys@0.9.47:       |                       ^~~~~~~~
warning: openssl-sys@0.9.47: build/expando.c:10:1: note: in expansion of macro ‘VERSION’
warning: openssl-sys@0.9.47:    10 | VERSION(OPENSSL, OPENSSL_VERSION_NUMBER)
warning: openssl-sys@0.9.47:       | ^~~~~~~

error: failed to run custom build command for `openssl-sys v0.9.47`

Caused by:
  process didn't exit successfully: `/mnt/d/work/file/rust/rustbuster/target/debug/build/openssl-sys-c5a482a9e0e49574/build-script-main` (exit status: 101)
  --- stdout
  cargo:rustc-cfg=const_fn
  cargo:rerun-if-env-changed=X86_64_UNKNOWN_LINUX_GNU_OPENSSL_LIB_DIR
  X86_64_UNKNOWN_LINUX_GNU_OPENSSL_LIB_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_LIB_DIR
  OPENSSL_LIB_DIR unset
  cargo:rerun-if-env-changed=X86_64_UNKNOWN_LINUX_GNU_OPENSSL_INCLUDE_DIR
  X86_64_UNKNOWN_LINUX_GNU_OPENSSL_INCLUDE_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_INCLUDE_DIR
  OPENSSL_INCLUDE_DIR unset
  cargo:rerun-if-env-changed=X86_64_UNKNOWN_LINUX_GNU_OPENSSL_DIR
  X86_64_UNKNOWN_LINUX_GNU_OPENSSL_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_DIR
  OPENSSL_DIR unset
  cargo:rustc-link-lib=ssl
  cargo:rustc-link-lib=crypto
  OPT_LEVEL = Some("0")
  TARGET = Some("x86_64-unknown-linux-gnu")
  HOST = Some("x86_64-unknown-linux-gnu")
  CC_x86_64-unknown-linux-gnu = None
  CC_x86_64_unknown_linux_gnu = None
  HOST_CC = None
  CC = None
  CFLAGS_x86_64-unknown-linux-gnu = None
  CFLAGS_x86_64_unknown_linux_gnu = None
  HOST_CFLAGS = None
  CFLAGS = None
  CRATE_CC_NO_DEFAULTS = None
  DEBUG = Some("true")
  CARGO_CFG_TARGET_FEATURE = Some("fxsr,sse,sse2")
  running: "cc" "-O0" "-ffunction-sections" "-fdata-sections" "-fPIC" "-g" "-fno-omit-frame-pointer" "-m64" "-Wall" "-Wextra" "-E" "build/expando.c"
  cargo:warning=build/expando.c:4:24: error: pasting "RUST_VERSION_OPENSSL_" and "(" does not give a valid preprocessing token
  cargo:warning=    4 | #define VERSION2(n, v) RUST_VERSION_##n##_##v
  cargo:warning=      |                        ^~~~~~~~~~~~~
  cargo:warning=build/expando.c:5:23: note: in expansion of macro ‘VERSION2’
  cargo:warning=    5 | #define VERSION(n, v) VERSION2(n, v)
  cargo:warning=      |                       ^~~~~~~~
  cargo:warning=build/expando.c:10:1: note: in expansion of macro ‘VERSION’
  cargo:warning=   10 | VERSION(OPENSSL, OPENSSL_VERSION_NUMBER)
  cargo:warning=      | ^~~~~~~
  exit status: 1

  --- stderr
  thread 'main' panicked at /home/root_cn/.cargo/registry/src/mirrors.sjtug.sjtu.edu.cn-4f7dbcce21e258a2/openssl-sys-0.9.47/build/main.rs:126:13:

  Header expansion error:
  Error { kind: ToolExecError, message: "Command \"cc\" \"-O0\" \"-ffunction-sections\" \"-fdata-sections\" \"-fPIC\" \"-g\" \"-fno-omit-frame-pointer\" \"-m64\" \"-Wall\" \"-Wextra\" \"-E\" \"build/expando.c\" with args \"cc\" did not execute successfully (status code exit status: 1)." }

  Failed to find OpenSSL development headers.

  You can try fixing this setting the `OPENSSL_DIR` environment variable
  pointing to your OpenSSL installation or installing OpenSSL headers package
  specific to your distribution:

      # On Ubuntu
      sudo apt-get install libssl-dev
      # On Arch Linux
      sudo pacman -S openssl
      # On Fedora
      sudo dnf install openssl-devel

  See rust-openssl README for more information:

      https://github.com/sfackler/rust-openssl#linux

  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
```

经过检查openssl与rust均为最新版本, 

```bash
[root_cn@archlinux target]$ sudo pacman -S rust
[sudo] password for root_cn:
warning: rust-1:1.77.2-1 is up to date -- reinstalling
resolving dependencies...
looking for conflicting packages...

Package (1)  Old Version  New Version  Net Change

extra/rust   1:1.77.2-1   1:1.77.2-1     0.00 MiB

Total Installed Size:  249.41 MiB
Net Upgrade Size:        0.00 MiB

:: Proceed with installation? [Y/n] n
[root_cn@archlinux target]$ sudo pacman -S openssl
warning: openssl-3.2.1-1 is up to date -- reinstalling
resolving dependencies...
looking for conflicting packages...

Package (1)   Old Version  New Version  Net Change

core/openssl  3.2.1-1      3.2.1-1        0.00 MiB

Total Installed Size:  11.45 MiB
Net Upgrade Size:       0.00 MiB

:: Proceed with installation? [Y/n] n
```

在网上找了一下, 查到资料, 在[rust-openssl的issues](https://github.com/sfackler/rust-openssl/issues/1227)中提到类似报错, 得到解释如下:

> If you are cross compiling to MUSL, you either need to point openssl-sys to the location that you have a copy of OpenSSL cross compiled to MUSL, or tell it to build a copy of OpenSSL itself with the vendored feature.
>
>	如果你是交叉编译到MUSL，你需要将openssl-sys指向你有一个交叉编译到MUSL的OpenSSL副本的位置，或者告诉它用vendored特性构建一个OpenSSL本身的副本。

由于不会rust, 依靠关键词"交叉编译"+"cargo"搜索到了[cargo交叉编译rust程序](https://blog.csdn.net/tyc880616/article/details/104371502), 顺着找到文件:

```
[root_cn@archlinux .cargo]$ cat ~/.cargo/config
[source.crates-io]
replace-with = 'sjtu' # 指定使用下面哪个源，修改为source.后面的内容即可

# 中国科学技术大学
[source.ustc]
registry = "https://mirrors.ustc.edu.cn/crates.io-index"

# 上海交通大学
[source.sjtu]
registry = "https://mirrors.sjtug.sjtu.edu.cn/git/crates.io-index/"

# 清华大学
[source.tuna]
registry = "https://mirrors.tuna.tsinghua.edu.cn/git/crates.io-index.git"

# rustcc社区
[source.rustcc]
registry = "https://code.aliyun.com/rustcc/crates.io-index.git"
```

没有找到交叉编译的设置, 由于本人不会rust, 线索断了, 尝试向大家寻求一波帮助, 非常感谢阅读.



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