FileReader.read
时间: 2023-11-02 10:07:06 浏览: 41
The FileReader.read() method is used to read a block of characters or bytes from a file. It reads from the current position in the file and returns the number of characters or bytes read. The method can be used with a FileReader object, which represents a connection to a file on disk. The FileReader.read() method can throw an IOException if there is an error reading from the file. It can also return -1 if the end of the file has been reached.
相关问题
FileReader fileReader = new FileReader("D:\\HeimaIT\\javaee\\collection-app\\src\\com\\itheima\\d3_collection_traverse\\111"); int read = fileReader.read(); System.out.println( (char) read);
这段代码打开了一个文件 "D:\HeimaIT\javaee\collection-app\src\com\itheima\d3_collection_traverse\111",使用FileReader类来读取文件内容。其中,fileReader.read()方法读取了文件的第一个字符,并将其存储在整型变量read中。由于read方法返回的是一个整数,因此需要将其强制转换为char类型,并使用System.out.println()方法将其输出到控制台。因此,这段代码的输出结果是文件中第一个字符。如果文件不存在或者无法读取,程序将会抛出IOException异常。
FileReader.readAsDataURL
FileReader.readAsDataURL is a method in JavaScript that allows you to read the contents of a specified file and return its data as a base64-encoded string. It is commonly used to read image files and convert them into a format that can be easily displayed or transmitted.
To use this method, you would first create an instance of the FileReader object and then call the readAsDataURL method, passing in the file you want to read as a parameter. Here's an example:
```javascript
// Create a new FileReader object
var reader = new FileReader();
// Set up an event handler for when the file has been read
reader.onload = function(event) {
// The result property contains the data as a base64-encoded string
var dataURL = event.target.result;
console.log(dataURL);
}
// Read the contents of the file as a data URL
reader.readAsDataURL(file);
```
In the example above, "file" represents the file you want to read. Once the file is read, the onload event will be triggered, and you can access the base64-encoded data URL through the event's result property.