将 java.io.inputstream 转换为 java.sql.blob
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convert java.io.inputstream to java.sql.blob
提问by CodeMed
How do I convert a java.io.inputstreamto a java.sql.blobusing pure java?
如何使用纯 Java将 a 转换java.io.inputstream为 a java.sql.blob？
EDIT:
编辑：
In response to tbodt's suggestions, I ran the following through the eclipse debugger. The debugger shows that myinputstreamhas content, but that blobremains nullat the end of the code. What do I need to do to fix this?
为了响应 tbodt 的建议，我通过 eclipse 调试器运行了以下内容。调试器显示myinputstream有内容，但blob保留null在代码的末尾。 我需要做什么来解决这个问题？
byte[] contents;
ByteArrayOutputStream output = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int count;
while ((count = myinputstream.read(buffer)) != -1){output.write(buffer, 0, count);}//debugger says myinputstream has blksize 16384, buffcount 12742, and max 127394 here
contents = output.toByteArray();
Blob blob = null;
try {blob = new SerialBlob(contents);}
catch (SerialException e) {e.printStackTrace();}
catch (SQLException e) {e.printStackTrace();}
someObject.setSomeBlobProperty(blob);//debugger says blob is null here
I also ran the IOUtilsapproach through the debugger, but got the exact same results, with a nullblobbut a populated myinputstream. How can I fix this?
我还IOUtils通过调试器运行了该方法，但得到了完全相同的结果，nullblob但是一个填充的myinputstream. 我怎样才能解决这个问题？
Blob blob = null;
try {
blob = new SerialBlob(IOUtils.toByteArray(myinputstream));//debugger says myinputstream has contents here.
someObject.setSomeBlobProperty(blob);//debugger says blob is null here
}
catch (SerialException e) {e.printStackTrace();}
catch (SQLException e) {e.printStackTrace();}
In both cases, the debugger says myinputstreamhas blksize16384, buffcount12742, and max127394 at the indicated locations, despite blobremaining null. I also checked the underlying mysqldatabase after running this code and confirmed that the blob field is empty.
在这两种情况下，调试器说myinputstream有blksize16384，buffcount12742和max127394在指定的位置，尽管blob剩余null。mysql运行此代码后，我还检查了底层数据库，并确认 blob 字段为空。
EDIT#2
编辑#2
I then ran the following through the eclipse debugger, which showed that the byte[]called contentremained empty after the attempts to populate it. So the resulting blobis empty, while the inputstreamdoes indeed continue to have the same content values as shown in edit#1 above:
然后我通过 eclipse 调试器运行以下命令，这表明在尝试填充它之后byte[]被调用的对象content仍然是空的。所以结果blob是空的，而inputstream确实继续具有与上面编辑#1 中所示相同的内容值：
Blob blob = null;
byte[] content = IOUtils.toByteArray(myinputstream);
try {
blob = new SerialBlob(content);//debugger says content is empty here
someObject.setSomeBlobProperty(blob);//debugger says blob is empty here.
}//debugger says myinputstream has the same values as in edit#1
catch (SerialException e) {e.printStackTrace();}
catch (SQLException e) {e.printStackTrace();}
回答by tbodt
The easy way:
简单的方法：
contents = IOUtils.toByteArray(in);
But for that, you need Apache Commons IO, which might be hard to add. If you don't want to use it, or can't, here's one way of doing it yourself;
但为此，您需要 Apache Commons IO，这可能很难添加。如果你不想使用它，或者不能使用它，这里有一种自己做的方法；
ByteArrayOutputStream output = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int count;
while ((count = input.read(buffer)) != -1)
output.write(buffer, 0, count);
contents = output.toByteArray();
回答by Angel O. Flores Torres
You can use the same:
您可以使用相同的：
Blob xmlForSign=null;
xmlForSign.getBinaryStream();
this method getBinaryStream() return an Inputfilestream.
这个方法 getBinaryStream() 返回一个 Inputfilestream。
