java 如何提供xml接口

有一个需求，web 必须提供xml的结果（接口），大家都是怎么做的？是写好xml文件，然后替换xml的结果吗？
或者是拼凑xml然后输出？这个好像很不专业。

直接有对bean2xml的工具

[code="java"]package com.fand.context.mapper;

import java.io.StringReader;
import java.io.StringWriter;
import java.util.Collection;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.namespace.QName;

import org.apache.commons.lang.StringUtils;
import org.springframework.http.converter.HttpMessageConversionException;
import org.springframework.util.Assert;

import com.google.common.base.Throwables;

/**

使用Jaxb2.0实现XML<->Java Object的Mapper. 在创建时需要设定所有需要序列化的Root对象的Class.
特别支持Root对象是Collection的情形.
@author yaoHT
*/
public class JaxbMapper {
/**
- 封装Root Element 是 Collection的情况.
  */
  public static class CollectionWrapper {
  @XmlAnyElement
  private Collection<?> collection;
  }
private static ConcurrentMap, JAXBContext> jaxbContexts = new ConcurrentHashMap, JAXBContext>();
/**
- 创建Marshaller并设定encoding(可为null). 线程不安全，需要每次创建或pooling。
  */
  public static Marshaller createMarshaller(final Class<?> clazz, final String encoding) {
  try {
  final JAXBContext jaxbContext = JaxbMapper.getJaxbContext(clazz);
```
final Marshaller marshaller = jaxbContext.createMarshaller();

marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);

if (StringUtils.isNotBlank(encoding)) {
    marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
}

return marshaller;
```
  } catch (final JAXBException e) {
  throw new RuntimeException(Throwables.getStackTraceAsString(e));
  }
  }
/**
- 创建UnMarshaller. 线程不安全，需要每次创建或pooling。
  */
  public static Unmarshaller createUnmarshaller(final Class<?> clazz) {
  try {
  final JAXBContext jaxbContext = JaxbMapper.getJaxbContext(clazz);
```
return jaxbContext.createUnmarshaller();
```
  } catch (final JAXBException e) {
  throw new RuntimeException(Throwables.getStackTraceAsString(e));
  }
  }
/**
- Xml->Java Object.
  */
  @SuppressWarnings("unchecked")
  public static T fromXml(final String xml, final Class clazz) {
  try {
  final StringReader reader = new StringReader(xml);
```
return (T) JaxbMapper.createUnmarshaller(clazz).unmarshal(reader);
```
  } catch (final JAXBException e) {
  throw new RuntimeException(Throwables.getStackTraceAsString(e));
  }
  }
private static JAXBContext getJaxbContext(final Class<?> clazz) {
Assert.notNull(clazz, "'clazz' must not be null");
JAXBContext jaxbContext = JaxbMapper.jaxbContexts.get(clazz);
if (jaxbContext == null) {
try {
jaxbContext = JAXBContext.newInstance(clazz, CollectionWrapper.class);
```
        JaxbMapper.jaxbContexts.putIfAbsent(clazz, jaxbContext);
    } catch (final JAXBException ex) {
        throw new HttpMessageConversionException("Could not instantiate JAXBContext for class [" + clazz
                + "]: " + ex.getMessage(), ex);
    }
}
return jaxbContext;
```
}
/**
- Java Collection->Xml without encoding, 特别支持Root Element是Collection的情形. */ public static String toXml(final Collection<?> root, final String rootName, final Class<?> clazz) { return JaxbMapper.toXml(root, rootName, clazz, null); }
/**
- Java Collection->Xml with encoding, 特别支持Root Element是Collection的情形.
  */
  public static String toXml(final Collection<?> root, final String rootName, final Class<?> clazz,
  final String encoding) {
  try {
  final CollectionWrapper wrapper = new CollectionWrapper();
```
wrapper.collection = root;

final JAXBElement<CollectionWrapper> wrapperElement = new JAXBElement<CollectionWrapper>(new QName(
        rootName), CollectionWrapper.class, wrapper);

final StringWriter writer = new StringWriter();

JaxbMapper.createMarshaller(clazz, encoding).marshal(wrapperElement, writer);

return writer.toString();
```
  } catch (final JAXBException e) {
  throw new RuntimeException(Throwables.getStackTraceAsString(e));
  }
  }
/**
- Java Object->Xml without encoding.
  */
  public static String toXml(final Object root) {
  final Class<?> clazz = root.getClass();
  return JaxbMapper.toXml(root, clazz, null);
  }
/**
- Java Object->Xml with encoding.
  */
  public static String toXml(final Object root, final Class<?> clazz, final String encoding) {
  try {
  final StringWriter writer = new StringWriter();
```
JaxbMapper.createMarshaller(clazz, encoding).marshal(root, writer);

return writer.toString();
```
  } catch (final JAXBException e) {
  throw new RuntimeException(Throwables.getStackTraceAsString(e));
  }
  }
/**
- Java Object->Xml with encoding.
  */
  public static String toXml(final Object root, final String encoding) {
  final Class<?> clazz = root.getClass();
  return JaxbMapper.toXml(root, clazz, encoding);
  }
  }
  [/code]

可以参考我写的基础开发平台解决方案：

https://git.oschina.net/fand/fand/blob/master/modules/fand-context/src/main/java/com/fand/context/mapper/JaxbMapper.java

现在流行用json。

可以用jaxb

XStream