dom4j读取xml格式化输出有空行情况

//如下为解析代码 
public static void main(String[] args) {
		 String str="<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
				+ "<data name=\"SYS_HEAD\">"
				+ "<struct>"
				+ "</struct>"
				+ "</data>"
				;
		    SAXReader reader=new SAXReader();
		    StringReader in=new StringReader(str);
		    Document doc;
		    StringWriter out=new StringWriter();
			try {
				doc = reader.read(in);
		         OutputFormat format = OutputFormat.createPrettyPrint(); 
		         format.setEncoding("UTF-8"); 
		         format.setIndent(true);    
		         format.setIndent("   ");   
		         format.setNewlines(true);  
		  
		         try { 
		             XMLWriter writer = new XMLWriter(out, format); 
		             writer.write(doc); 
		             writer.close(); 
		         } catch (Exception ex) { 
		             System.out.println(ex.getMessage()); 
		         } 
			    
			    
			} catch (DocumentException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} 
		    System.out.print(out.toString());
	}
//输入后结果：

<?xml version="1.0" encoding="UTF-8"?>

<data name="SYS_HEAD">
   <struct/>
</data>

 //问题，不管如何格式化，输出结果中的第一行与第三行之间这行都去不掉，不知道大家有没有遇到，求解决方法！！！