java.io.UTFDataFormatException: Invalid byte 2 of 2-byte UTF-8 sequence

今天改bug时遇到的问题，以前用的时候没有报错，用了一段时间了才报出来错。实现的功能是将一个ftl的模板转换为PDF导出来。

java.io.UTFDataFormatException: Invalid byte 2 of 2-byte UTF-8 sequence.
at org.apache.xerces.impl.io.UTF8Reader.invalidByte(Unknown Source)
at org.apache.xerces.impl.io.UTF8Reader.read(Unknown Source)
at org.apache.xerces.impl.XMLEntityScanner.load(Unknown Source)
at org.apache.xerces.impl.XMLEntityScanner.skipChar(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:121)

Java类：

DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
EntityResolver er = new EntityResolver() {
@Override
public InputSource resolveEntity(String publicId, String systemId)
{
if(publicId.equals("-//W3C//DTD XHTML 1.0 Transitional//EN"))
                 {
                    String dtd_uri = getRequest().getSession().getServletContext()
            .getRealPath("dtd/xhtml1-transitional.dtd");
                     return new InputSource(dtd_uri);
                 }
return null;
}
};
builder.setEntityResolver(er);
Document doc = builder.parse(new ByteArrayInputStream(htmlStr.getBytes()));  提示这行代码错误
ITextRenderer renderer = new ITextRenderer();
renderer.setDocument(doc, null);

ftl文件：

 
 

结果导出PDF的时候报了上面的错误，

由于声明的 htmlStr转换字节数组的时候使用默认的编码是gbk的

查明原因后，将原函数修订如下

Document doc = builder.parse(new ByteArrayInputStream(htmlStr.getBytes("utf-8")));