blob | 易学教程

Phonegap/Cordova 3.6 - Download of file through blob:file

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问题 We have an app using Phonegap 3.6.3 and built with Phonegap build . As part of this app, we need to download a file onto the device of the user. The file might be a .pdf, an image or any binary file. We hope to download the file with a blob:file link in the app, and not use a plugin such as file-transfer. The file is converted from Base64 data and a Blob object is created. An objectURL is generated through window.URL.createObjectURL() and this is added to the href attribute of an a element.

deserialize java object from a blob

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问题 first of all, i apologize, i'm about to ask a set of dumb questions. i don't know java AT ALL and i don't know if we are allowed to ask questions like these. if not - delete my topic. there's a table in oracle that stores a blob. it's binary and i'm able to decode it, the output looks like this ¬í sr /com.epam.insure.credentialing.forms.StorageBeanÀÓ ¯w/§ L variablest Ljava/util/Map;xpsr java.util.HashMapÚÁÃ`Ñ F loadFactorI thresholdxp?@ w t $_hasCompletedt t $_wf_progresssr java.lang

【vue】纯前端导出表格数据（vue+element-ui）

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1.安装依赖安装依赖xlsx，file-saver npm install --save xlsx file-saver 2.在组件中引入 import FileSaver from 'file-saver' import XLSX from 'xlsx' 3.添加下载方法 #out-table为table节点的id outTab ( ) { /* 从表生成工作簿对象 */ var xlsxParam = { raw : true } // 导出的内容只做解析，不进行格式转换 var wb = XLSX . utils . table_to_book ( document . querySelector ( "#Console" ) , xlsxParam ) ; /* 获取二进制字符串作为输出 */ var wbout = XLSX . write ( wb , { bookType : "xlsx" , bookSST : true , type : "array" } ) ; var date = this . getTime ( ) ; try { FileSaver . saveAs ( //Blob 对象表示一个不可变、原始数据的类文件对象。 //Blob 表示的不一定是JavaScript原生格式的数据。 //File 接口基于Blob，继承了 blob

Create json file using blob

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问题 I have written json code in string and i want to send it using xmlhttp as .json file. Is it possible to do it with blob? var cleanScript = { 'type': 'script', 'api_key': api_key, 'data': data, 'inputs': inputs, 'timeoutSeconds': timeoutSeconds }; var jsonse = JSON.stringify(cleanScript, null, 2); Now json to blob? 回答1: Try something like this var cleanScript = { 'type': 'script', 'api_key': api_key, 'data': data, 'inputs': inputs, 'timeoutSeconds': timeoutSeconds }; var jsonse = JSON

filesize from a String

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问题 how can i get the "filesize" from a string in php? I put the string in a mysql database as a blob and i need to store the size of the blob. My solution was to create a temp file and put the string into the temp file. now i can get the filesize from the "string". but that solution is not good... greetings 回答1: It depends. If you have mbstring function overloading enabled, the only call that will work will be mb_strlen($string, '8bit'); . If it's not enabled, strlen($string) will work fine as

Inline BLOB / BINARY data types in SQL / JDBC

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问题 Let's say I want to avoid using bind variables in JDBC and run SQL using "ad-hoc" statements, e.g: connection.createStatement().executeQuery("SELECT ..."); Is there any convention / JDBC escape syntax to inline BLOB data types? I know that H2 has this syntax: INSERT INTO lob_table VALUES (X'01FF'); But that's not a standard. Any general solutions? Note, I'm interested in a general approach. I know that this can turn out to be terribly inefficient. 回答1: There probably isn't a JDBC escape

MySQL - Base64 vs BLOB

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问题 For the sake of simplicity, suppose I'm developing a mobile app like Instagram. Users can download images from the server, and upload images of their own. Currently the server stores all images (in reality, just small thumbnails) in a MySQL database as BLOBs. It seems that the most common way to transfer images is by using Base64 encoding, which leaves me with two options: Server stores all images as BLOBs. To upload an image, client encodes it into Base64 string, then sends it to the server.

Saving base64 image with Filesaver.js

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问题 I am getting multiple Base64 URIs of JPG images. I need to save them as jpg files. I'm trying to use FileSaver.js, but its not working for me. I have used filesaver.js before, when I was getting images from aws-sdk, in which, the data was in buffer form and it worked. However, its not working for me with base64 string. var base64 = '/9j/4AAQSkZJRgABAQAAAQABAAD//gA7Q1JFQVRPUjogZ2QtanBlZyB2MS4wICh1c2luZyBJSkcgSlBFRyB2ODApLCBxdWFsaXR5ID0gODUK

Java BLOB to image file

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问题 I have a BLOB that is retrieved from a MySQL database as follows: Blob imageBlob; while (rs.next()) { imageBlob= rs.getBlob("face"); } after that my imageBlob is something like this: data:image/png;base64,iVBORw0KGgoAAAANSUhE................ I've been googling around but I haven't found any solution to my problem: how do I create an image file and save it on the disk from this BLOB? 回答1: imageBlob is storing the base64 representation of your image data. For storing that onto your disk you

What's the best way to send pictures to a browser when they have to be stored as blobs in a database?

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I have an existing database containing some pictures in blob fields. For a web application I have to display them. What's the best way to do that, considering stress on the server and maintenance and coding efforts. I can think of the following: "Cache" the blobs to external files and send the files to the browser. Read them from directly the database every time it's requested. Some additionals facts: I cannot change the database and get rid of the blobs alltogether and only save file references in the database (Like in the good ol' Access days), because the database is used by another