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我正在使用Oracle 11g数据库，jdk1.6.0_45 我正在尝试从数据库xml中以 a 的形式获取文件blob并使用DOM parser. 我正在尝试解析blob对象并将输出内容写入控制台。这是我的代码片段-

String outputFile = "C:\\DEVELOPMENT_PROJECTS\\result1.xml";
String myDocId = "12345";

java.sql.PreparedStatement pstmt = connection.prepareStatement("SELECT * FROM my_document WHERE my_doc_id = '" + myDocID + "'"); // connection is of type java.sql.Connection

java.sql.ResultSet rs = pstmt.executeQuery(); // always returns only one row.

rs.next();

java.sql.Blob blobObj = rs.getBlob("DOC_BLOB");

java.io.InputStream is = blobObj.getBinaryStream();

java.io.FileOutputStream fos = new FileOutputStream(outputFile);

while (((byte) is.read()) != -1) {
    fos.write((byte) is.read());
} // tried writing in output xml file too. this writes junk data into the output file

outputFromInputStream(is);

这是堆栈跟踪的异常-

oracle.jdbc.driver.T4CConnection@19a32e0
[Fatal Error] :1:1: Premature end of file.
org.xml.sax.SAXParseException: Premature end of file.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:246)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:284)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:124)
    at com.dummy.project.lang.DataTest.newDocumentFromInputStream(DataTest.java:197)
    at com.dummy.project.lang.DataTest.main(DataTest.java:75)
<?xml version="1.0" encoding="UTF-8" standalone="no"?>

我检查了 XML 文件的有效性。在第一行之后<?xml version="1.0" encoding="UTF-8" standalone="no"?>有一个有效的<tag>

但是，我能够成功地xml从驱动器等物理位置读取文件C:\并将其写入输出 xml。这就是我的做法（请记住，获取InputStream数据和之后的剩余步骤很常见） -

java.io.File file = new File("C:\\myLocalXMLFile.xml");

InputStream is = new FileInputStream(file);
outputFromInputStream(is);

这是常用的方法-

private void outputFromInputStream(InputStream is) {
javax.xml.parsers.DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

javax.xml.parsers.DocumentBuilder builder = factory.newDocumentBuilder();

org.w3c.dom.Document doc = builder.parse(in); // Exception is thrown here

java.io.StringWriter sw = new StringWriter();

javax.xml.transform.dom.DOMSource domSource = new DOMSource(xmldom);

javax.xml.transform.stream.StreamResult streamResult = new StreamResult(sw);

javax.xml.transform.TransformerFactory tf = TransformerFactory.newInstance();

javax.xml.transform.Transformer transformer = tf.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "yes");
transformer.setOutputProperty("http://xml.apache.org/xslt}indent-amount", "10");
transformer.transform(domSource, streamResult);
System.out.println(sw.toString());
}
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1 回答 1

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出于某种原因，以下代码片段有效 -

BufferedReader br = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = br.readLine()) != null) {
    sb.append(line);
}
System.out.println(sb.toString());
于 2017-01-03T07:21:21.757 回答