js根据图片地址转DataURL和DataURL转Blob 1.根据图片URL直接获取到DataUrlfunction convertImgToDataURLviaCanvas(url, callback, outputFormat){ var img = new Image(); img.crossOrigin = 'Anonymous'; img.onload = function(){ var canvas = document.createElement('CANVAS'); var ctx = canvas.getContext('2d'); var dataURL; canvas.height = this.height; canvas.width = this.width; ctx.drawImage(this, 0, 0); dataURL = canvas.toDataURL(outputFormat); callback(dataURL); canvas = null; }; img.src = url; }function convertFileToDataURLviaFileReader(url, callback){ var xhr = new XMLHttpRequest(); xhr.responseType = 'blob'; xhr.onload = function() { var reader = new FileReader(); reader.onloadend = function () { callback(reader.result); } reader.readAsDataURL(xhr.response); }; xhr.open('GET', url); xhr.send(); }2.DataURL转Blobfunction dataURLtoBlob(dataurl) { var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1], bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n); while(n--){ u8arr[n] = bstr.charCodeAt(n); } return new Blob([u8arr], {type:mime}); }

Andorid Studio问题“gradle sync failed” 1.选择gradleAndroid Studio安装后可能会出现gradle sync failed错误首先打开设置界面（Ctrl+Alt+S）选择 Build,Execution,Deployment选择Gradle重新设置你的Service directory path目录安装Android Studio时默认会安装Gradle在 "C:/Users/用户名/.gradle" 此路径下，你只需要把 Service directory path 的路径修改为更详细点就可以了（eg:C:/Users/EraJi/.gradle/wrapper/dists/gradle-4.4-all）。直接指定路径中的 gradle 文件夹。你也可以自己下载对应版本的Gradle，然后把这个路径指向你下载好的Gradle目录。下载地址：这里就不细讲了，其实我弄不太懂重新编译下工程就可以了2.检查Jdk选择自带的jdk11或者默认的jdk83.sdk设置在目录 D:\\{YOUR_SDK_PATH}\Android\Sdk\tools\bin 执行命令sdkmanager --licenses一路选择 yes

windows配置jdk环境变量 1.打开系统环境变量配置2.添加 JAVA_HOMED:\Program Files\Java\jdk1.8.0_253.修改 Path%JAVA_HOME%\bin;%JAVA_HOME%\jre\bin;4.添加 CLASSPATH%JAVA_HOME%\lib;%JAVA_HOME%\lib\tools.jar;5.验证java -versionjavajavac

CentOS配置jdk环境变量 1.下载linux版1.8JDK包安装版本 jdk-8u191-linux-x64.tar.gz 为例2.解压安装包到指定目录tar -zxvf jdk-8u191-linux-x64.tar.gz3.配置环境变量并生效（1）root用户打开配置文件 /etc/profilevi /etc/profile在末尾添加以下内容：export JAVA_HOME=/home/$USER/programs/soft/jdk1.8.0_381 export CLASSPATH=.:${JAVA_HOME}/jre/lib/rt.jar:${JAVA_HOME}/lib/dt.jar:${JAVA_HOME}/lib/tools.jar export PATH=$PATH:${JAVA_HOME}/bin（2）普通用户vi ~/.bash_profile在.bash_profile文件中填入如下语句：export PATH export JAVA_HOME=/home/$USER/programs/soft/jdk1.8.0_381 export PATH=$JAVA_HOME/bin:$PATH export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar4.使配置文件生效source /etc/profilesource ~/.bash_profile5.检验java环境java -version出现以下内容：java version "1.8.0_381" Java(TM) SE Runtime Environment (build 1.8.0_381-b12) Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)

Error: Cannot find module '@dcloudio/uni-cli-i18n' h5PlusApp编译报错：internal/modules/cjs/loader.js:883 15:18:42.357 throw err; 15:18:42.365 ^ 15:18:42.366 Error: Cannot find module '@dcloudio/uni-cli-i18n' 15:18:42.371 Require stack: 15:18:42.371 - D:\ws\code\package\sss(Separate)\apk\node_modules\@dcloudio\vue-cli-plugin-hbuilderx\index.js 15:18:42.378 - D:\ws\code\package\sss(Separate)\apk\node_modules\@vue\cli-service\lib\Service.js 15:18:42.379 - D:\ws\code\package\sss(Separate)\apk\node_modules\@vue\cli-service\bin\vue-cli-service.js 15:18:42.383 at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15) 15:18:42.387 at Function.Module._load (internal/modules/cjs/loader.js:725:27) 15:18:42.387 at Module.require (internal/modules/cjs/loader.js:952:19) 15:18:42.390 at require (internal/modules/cjs/helpers.js:88:18) 15:18:42.391 at Object.<anonymous> (D:\ws\code\package\sss(Separate)\apk\node_modules\@dcloudio\vue-cli-plugin-hbuilderx\index.js:3:17) 15:18:42.397 at Module._compile (internal/modules/cjs/loader.js:1063:30) 15:18:42.400 at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10) 15:18:42.403 at Module.load (internal/modules/cjs/loader.js:928:32) 15:18:42.403 at Function.Module._load (internal/modules/cjs/loader.js:769:14) 15:18:42.406 at Module.require (internal/modules/cjs/loader.js:952:19) { 15:18:42.406 code: 'MODULE_NOT_FOUND', 15:18:42.412 requireStack: [ 15:18:42.415 'D:\\ws\\code\\package\\sss(Separate)\\apk\\node_modules\\@dcloudio\\vue-cli-plugin-hbuilderx\\index.js', 15:18:42.417 'D:\\ws\\code\\package\\sss(Separate)\\apk\\node_modules\\@vue\\cli-service\\lib\\Service.js', 15:18:42.419 'D:\\ws\\code\\package\\sss(Separate)\\apk\\node_modules\\@vue\\cli-service\\bin\\vue-cli-service.js' 15:18:42.420 ] 15:18:42.422 }npm add -D @dcloudio/uni-cli-i18n @dcloudio/uni-i18n