将InputStream（Image）转换为ByteArrayInputStream

Question

不确定我该怎么做。任何帮助，将不胜感激

Answer 1

从输入流中读取并写入ByteArrayOutputStream，然后调用其toByteArray()以获取字节数组。

在字节数组周围创建一个ByteArrayInputStream以便从中读取。

这里是一个快速测试：

import java.io.*;

public class Test {


       public static void main(String[] arg) throws Throwable {
          File f = new File(arg[0]);
          InputStream in = new FileInputStream(f);

          byte[] buff = new byte[8000];

          int bytesRead = 0;

          ByteArrayOutputStream bao = new ByteArrayOutputStream();

          while((bytesRead = in.read(buff)) != -1) {
             bao.write(buff, 0, bytesRead);
          }

          byte[] data = bao.toByteArray();

          ByteArrayInputStream bin = new ByteArrayInputStream(data);
          System.out.println(bin.available());
       }
}

Answer 2

或首先将其转换为字节数组，然后转换为bytearrayinputstream。

File f = new File(arg[0]);
InputStream in = new FileInputStream(f);
// convert the inpustream to a byte array
byte[] buf = null;
try {
    buf = new byte[in.available()];
    while (in.read(buf) != -1) {
    }
} catch (Exception e) {
    System.out.println("Got exception while is -> bytearr conversion: " + e);
}
// now convert it to a bytearrayinputstream
ByteArrayInputStream bin = new ByteArrayInputStream(buf);

Answer 3

您可以使用org.apache.commons.io。IOUtils＃toByteArray（java.io.InputStream）

InputStream is = getMyInputStream();
ByteArrayInputStream bais = new ByteArrayInputStream(IOUtils.toByteArray(is));