如何在 javascript 中傳輸大文件下載的文件塊並重建它？

Question

I need to download large files using files chunks for which JAVA spring server is developed and files are recived at UI via REST api. 尋找解決方案來加入 javascript 中的所有塊

Answer 1

我不確定您的要求，但希望這會對您有所幫助

首先，您需要使用async function 中的 fetch 調用來獲取文件

response = await fetch(url);

然后之后您將能夠從響應中獲取閱讀器const reader = response.body.getReader();

您可以通過測量該存儲總文件大小的進度來跟蹤獲取

const contentLength = +response.headers.get('Content-Length');

為了跟蹤接收到的字節let receivedLength = 0;

存儲收到的塊

let chunks = []; // array of received binary chunks (comprises the body)

之后做一個while循環，它將無休止地運行

while(true) {
          const {done, value} = await reader.read();

          if (done) {
            break;
          }

          chunks.push(value);
          receivedLength += value.length;
            
          let compleated = Math.round(receivedLength/contentLength*100);

          console.log(`Received ${receivedLength} of ${contentLength}`)
        }

 after the while loop has broken you can check if the transfer is fully completed or not

然后你可以從我們存儲數據塊的數組中創建一個 blob

let blob = new Blob(chunks);

那么你可以使用這個blob