如何创建一个像这样的简单xml文档

<bo type=\"Employee\" id=\"0000012f41bce2a865f8616b0010007c0008008b\">
  <username>marv</username>
</bo>

username

Element bo = testDoc.createElement(\"bo\");
        bo.setAttribute(\"type\", \"Employee\");
        bo.setAttribute(\"id\", emp.getId());

Element bo = testDoc.createElement(\"bo\");
bo.setAttribute(\"type\", \"Employee\");
bo.setAttribute(\"id\", emp.getId());
//create a username element
Element username = testDoc.createElement(\"username\");
//add a text value to the username element
username.appendChild(testDoc.createTextNode(\"marv\"));
//add the username element as child of bo element
bo.appendChild(username);