add xml 2 bean 互转utils;

解决：
BeanUtil.beanToMap(outer)只能解析第一层，如果想多层解析，考虑使用JSONUtil的bug;

生产环境，常见是要 解析多层，而不是 只解析第一层；

hutool-core/src/main/java/cn/hutool/core/util/XmlBeanUtil.java

@@ -0,0 +1,102 @@
+package cn.hutool.core.util;
+
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.Marshaller;
+import javax.xml.bind.Unmarshaller;
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * xml和Bean互转工具类，不依赖第三方库；需要使用到：javax.xml 包
+ * @author dazer
+ * 相关介绍：
+ * <ul>
+ * <li><a href=' java实体 和 xml相互转换'>https://www.cnblogs.com/yanghaolie/p/11110991.html</a></li>
+ * <li><a href=' https://my.oschina.net/u/4266515/blog/3330113<'>JAXB "有两个名为 "**" 的属性,类的两个属性具有相同名称 "**""解决方案</a>/li>
+ * </ul>
+ */
+public class XmlBeanUtil {
+	/**
+	 * JavaBean转换成xml
+	 *
+	 * @param obj
+	 * @param encoding eg: utf-8
+	 * @param format eg: true
+	 * @return
+	 */
+	public static String convertToXml(Object obj, String encoding, boolean format) {
+		String result = null;
+		StringWriter writer = null;
+		try {
+			JAXBContext context = JAXBContext.newInstance(obj.getClass());
+			Marshaller marshaller = context.createMarshaller();
+			marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, format);
+			marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
+			writer = new StringWriter();
+			marshaller.marshal(obj, writer);
+			result = writer.toString();
+		} catch (Exception e) {
+			throw new RuntimeException("convertToXml 错误：" + e.getMessage(), e);
+		} finally {
+			if (writer != null){
+				try {
+					writer.close();
+				} catch (IOException e) {
+					e.printStackTrace();
+				}
+			}
+		}
+		return result;
+	}
+
+	public static String convertToXml(Object obj) {
+		return convertToXml(obj, StandardCharsets.UTF_8.toString(), true);
+	}
+
+	/**
+	 * xml转换成JavaBean
+	 *
+	 * @param xml
+	 * @param c
+	 * @return
+	 */
+	@SuppressWarnings("unchecked")
+	public static <T> T convertToJava(String xml, Class<T> c) {
+		if (xml == null || "".equals(xml))
+			return null;
+		T t = null;
+		StringReader reader = null;
+		try {
+			JAXBContext context = JAXBContext.newInstance(c);
+			Unmarshaller unmarshaller = context.createUnmarshaller();
+			reader = new StringReader(xml);
+			t = (T) unmarshaller.unmarshal(reader);
+		} catch (Exception e) {
+			throw new RuntimeException("convertToJava1 错误：" + e.getMessage(), e);
+		} finally {
+			if (reader != null)
+				reader.close();
+		}
+		return t;
+	}
+
+	@SuppressWarnings("unchecked")
+	public static <T> T convertToJava(File filePath, Class<T> c) throws IOException {
+		if (!filePath.exists())
+			return null;
+		T t = null;
+		FileReader reader = null;
+		try {
+			JAXBContext context = JAXBContext.newInstance(c);
+			Unmarshaller unmarshaller = context.createUnmarshaller();
+			reader = new FileReader(filePath);
+			t = (T) unmarshaller.unmarshal(reader);
+		} catch (Exception e) {
+			throw new RuntimeException("convertToJava2 错误：" + e.getMessage(), e);
+		} finally {
+			if (reader != null)
+				reader.close();
+		}
+		return t;
+	}
+}

hutool-core/src/test/java/cn/hutool/core/util/XmlBeanUtilTest.java

@@ -0,0 +1,103 @@
+package cn.hutool.core.util;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import javax.xml.bind.annotation.*;
+
+/**
+ * {@link XmlBeanUtil} 工具类
+ *
+ * @author dazer
+ * 测试 xml 和 bean 互转工具类
+ */
+public class XmlBeanUtilTest {
+
+	@Test
+	public void convertToXmlTest() {
+		SchoolVo schoolVo = new SchoolVo();
+		schoolVo.setSchoolName("西安市第一中学");
+		schoolVo.setSchoolAddress("西安市雁塔区长安堡一号");
+
+		SchoolVo.RoomVo roomVo = new SchoolVo.RoomVo();
+		roomVo.setRoomName("101教室");
+		roomVo.setRoomNo("101");
+		schoolVo.setRoom(roomVo);
+
+		String xmlStr = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n" +
+				"<school>\n" +
+				"    <school_name>西安市第一中学</school_name>\n" +
+				"    <school_address>西安市雁塔区长安堡一号</school_address>\n" +
+				"    <room>\n" +
+				"        <room_no>101</room_no>\n" +
+				"        <room_name>101教室</room_name>\n" +
+				"    </room>\n" +
+				"</school>\n";
+		Assert.assertEquals(XmlBeanUtil.convertToXml(schoolVo), xmlStr);
+	}
+
+
+	@XmlRootElement(name = "school")
+	@XmlAccessorType(XmlAccessType.FIELD)
+	private static final class SchoolVo {
+		@XmlElement(name = "school_name", required = true)
+		private String schoolName;
+		@XmlElement(name = "school_address", required = true)
+		private String schoolAddress;
+		@XmlElement(name = "room", required = true)
+		private RoomVo room;
+
+		@XmlTransient
+		public String getSchoolName() {
+			return schoolName;
+		}
+
+		public void setSchoolName(String schoolName) {
+			this.schoolName = schoolName;
+		}
+
+		@XmlTransient
+		public String getSchoolAddress() {
+			return schoolAddress;
+		}
+
+		public void setSchoolAddress(String schoolAddress) {
+			this.schoolAddress = schoolAddress;
+		}
+
+		@XmlTransient
+		public RoomVo getRoom() {
+			return room;
+		}
+
+		public void setRoom(RoomVo room) {
+			this.room = room;
+		}
+
+		@XmlAccessorType(XmlAccessType.FIELD)
+		public static final class RoomVo {
+			@XmlElement(name = "room_no", required = true)
+			private String roomNo;
+			@XmlElement(name = "room_name", required = true)
+			private String roomName;
+
+			@XmlTransient
+			public String getRoomNo() {
+				return roomNo;
+			}
+
+			public void setRoomNo(String roomNo) {
+				this.roomNo = roomNo;
+			}
+
+			@XmlTransient
+			public String getRoomName() {
+				return roomName;
+			}
+
+			public void setRoomName(String roomName) {
+				this.roomName = roomName;
+			}
+		}
+	}
+}