Mybatis Custom Type handler: call FileInputStream.close() after query being executed - jdbc

Question

I am trying to implement MyBatis custom type handler for File using FileInputStream.
here is my code for setting:
#MappedJdbcTypes(JdbcType.LONGVARBINARY)
public class FileByteaHandler extends BaseTypeHandler<File> {
#Override
public void setNonNullParameter(PreparedStatement ps, int i, File file, JdbcType jdbcType) throws SQLException{
try {
FileInputStream fis = new FileInputStream(file);
ps.setBinaryStream(1, fis, (int) file.length());
} catch(FileNotFoundException ex) {
Logger.getLogger(FileByteaHandler.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
My question is:
I can not close this FileInputStream at the end of this method, otherwise MyBatis will not be able to read the data from it. In fact, I do not know where I can close the FileInputStream. Is there a way to call close() after the query being excuted in MyBatis.
Thanks in advance,
UPDATE
Thanks for Jarandinor's help. Here is my code for this type handler. and hopefully it can help someone:
#MappedJdbcTypes(JdbcType.LONGVARBINARY)
public class FileByteaHandler extends BaseTypeHandler<File> {
#Override
public void setNonNullParameter(PreparedStatement ps, int i, File file, JdbcType jdbcType) throws SQLException {
try {
AutoCloseFileInputStream fis = new AutoCloseFileInputStream(file);
ps.setBinaryStream(1, fis, (int) file.length());
} catch(FileNotFoundException ex) {
Logger.getLogger(FileByteaHandler.class.getName()).log(Level.SEVERE, null, ex);
}
}
#Override
public File getNullableResult(ResultSet rs, String columnName) throws SQLException {
File file = null;
try(InputStream input = rs.getBinaryStream(columnName)) {
file = getResult(rs, input);
} catch(IOException e) {
System.out.println(e.getMessage());
}
return file;
}
public File creaetFile() {
File file = new File("e:/target-file"); //your temp file path
return file;
}
private File getResult(ResultSet rs, InputStream input) throws SQLException {
File file = creaetFile();
try(OutputStream output = new FileOutputStream(file)) {
int bufSize = 0x8000000;
byte buf[] = new byte[bufSize];
int s = 0;
int tl = 0;
while( (s = input.read(buf, 0, bufSize)) > 0 ) {
output.write(buf, 0, s);
tl += s;
}
output.flush();
} catch(IOException e) {
System.out.println(e.getMessage());
}
return file;
}
#Override
public File getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
File file = null;
try(InputStream input = rs.getBinaryStream(columnIndex)) {
file = getResult(rs, input);
} catch(IOException e) {
System.out.println(e.getMessage());
}
return file;
}
#Override
public File getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
throw new SQLException("getNullableResult(CallableStatement cs, int columnIndex) is called");
}
private class AutoCloseFileInputStream extends FileInputStream {
public AutoCloseFileInputStream(File file) throws FileNotFoundException {
super(file);
}
#Override
public int read() throws IOException {
int c = super.read();
if(available() <= 0) {
close();
}
return c;
}
public int read(byte[] b) throws IOException {
int c = super.read(b);
if(available() <= 0) {
close();
}
return c;
}
public int read(byte[] b, int off, int len) throws IOException {
int c = super.read(b, off, len);
if(available() <= 0) {
close();
}
return c;
}
}
}
public AutoCloseFileInputStream(File file) throws FileNotFoundException {
super(file);
}
#Override
public int read() throws IOException {
int c = super.read();
if( c == -1 ) {
close();
}
return c;
}
public int read(byte[] b) throws IOException {
int c = super.read(b);
if( c == -1 ) {
close();
}
return c;
}
public int read(byte[] b, int off, int len) throws IOException {
int c = super.read(b, off, len);
if(available() <= 0) {
close();
}
return c;
}
}

Answer 1

I don't know a good way to close stream after query execution.
Method 1:
read the file to byte []
(note: in jdk 7 you can use Files.readAllBytes(Paths.get(file.getPath()));)
and use:
ps.setBytes(i, bytes);
2: or create your own class inherited from FileInputStream and override public native int read() throws IOException; method, when the end of the file is reached, close the stream:
#Override
public int read() throws IOException {
int c = super.read();
if(c == -1) {
super.close();
}
return c;
}
Maybe you should override and public int read(byte[] b) throws IOException too,
it's depends on the jdbc implementation.
3: you can change your FileByteaHandler:
1) add list of FileInputStream field;
2) put opened InputStream to that list in setNonNullParameter;
3) add closeStreams() method, where you close and remove all InputStream from list.
And invoke this method after you have invoked your mapper method: session.getConfiguration().getTypeHandlerRegistry().getMappingTypeHandler(FileByteaHandler.class).closeStreams();
Or use mybatis plugin system to run above command.