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XStream解析XML文本并用反射机制转换为对象
xml文本格式是网络通信中最常用的格式,最近特别研究了一下如何解析xml文本并转换为对象,现在分享一下我最近的学习成果~
先列一下本例中需要解析的xml文本:
Xml代码
<results name="list">
<row pubtime="2016-04-13 16:40:13" author="APP" id="140" title="什么是公告" content="公告,是公开宣告。" />
<row pubtime="2016-04-13 16:36:50" author="网站" id="138" title="12345678" content="12345678" />
<row pubtime="2016-04-06 15:02:44" author="网站" id="134" title="关于网站用户注册流程说明1" content="关于用户注册流程说明" />
<row pubtime="2016-03-30 18:32:13" author="APP" id="126" title="关于网站使用说明" content="测试" />
<row pubtime="2016-03-30 18:29:26" author="网站" id="125" title="关于手机App使用说明" content="123" />
</results>
讲一下我的思路,我选择使用XStream来解析xml文本,因为xstream在转换对象方面会比dom4j更优秀一些,它是通过注解方式来声明对应结点的,在操作上会更直观方便。首先会将整个文本转换成一个Results类对象,而每一个row结点作为一个HashMap放入到Results类对象的List列表中,最后会将每一个HashMap读取出来通过JAVA的反射机制转换为Info对象,并生成List列表。下载
Info类代码
public class Info {
private String id;
private String title;
private String content;
private String author;
private String pubtime;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public String getPubtime() {
return pubtime;
}
public void setPubtime(String pubtime) {
this.pubtime = pubtime;
}
@Override
public String toString() {
return "Info [author=" + author + ", content=" + content + ", id=" + id
+ ", pubtime=" + pubtime + ", title=" + title + "]";
}
}
Row类代码
@XStreamConverter(RowConverter.class)
public class Row extends HashMap<String, String> {
private static final long serialVersionUID = 5619951409573339302L;
} 下载
Results代码
@XStreamAlias("results")
public class Results {
@XStreamAlias("name")
@XStreamAsAttribute
private String name;
@XStreamImplicit(itemFieldName = "row")
private List<Row> rows;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Row> getRows() {
return rows;
}
public void setRows(List<Row> rows) {
this.rows = rows;
}
}
Rowconverter类代码
public class RowConverter extends AbstractCollectionConverter {
public RowConverter(Mapper mapper) {
super(mapper);
// TODO Auto-generated constructor stub
}
@Override
public boolean canConvert(Class arg0) {
// TODO Auto-generated method stub
return Row.class.equals(arg0);
}
下载
@Override
public void marshal(Object arg0, HierarchicalStreamWriter writer,
MarshallingContext arg2) {
// TODO Auto-generated method stub
Row map = (Row) arg0;
for (Iterator iterator = map.entrySet().iterator(); iterator.hasNext();) {
Map.Entry entry = (Map.Entry) iterator.next();
writer.addAttribute(entry.getKey().toString(), entry.getValue().toString());
}
}
@Override
public Object unmarshal(HierarchicalStreamReader reader,
UnmarshallingContext context) {
// TODO Auto-generated method stub
Row map = new Row();
populateMap(reader, context, map);
return map;
}
protected void populateMap(HierarchicalStreamReader reader, UnmarshallingContext context, Row map) {
Iterator<String> iterator = reader.getAttributeNames();
while (iterator.hasNext()) {
Object key = iterator.next();
String value = reader.getAttribute((String) key);
map.put(key.toString(), value.toString());
}
}
}
RowConverter是一个转换器类,作用是将每一个row结点转变一个HashMap。
测试类下载:
Java代码
public class Xstream {
private static String xml;
public static void main(String[] args) throws Exception{
//初始化
init();
XStream xstream = new XStream(new XppDriver(new XmlFriendlyReplacer("_-", "_")));
//解析xml文本
xstream.processAnnotations(Results.class);
Results results = (Results) xstream.fromXML(xml);
//将解析出来的Results类对象转化成list列表
List<Info> list = createList(Info.class,results);
for(int i=0;i<list.size();i++){
//打印
Info info = list.get(i);
System.out.println(info.toString());
}
}
public static void init(){
//初始化xml文本
xml ="<results name=\"list\"><row pubtime=\"2016-04-13 16:40:13\" author=\"APP\" id=\"140\" title=\"什么是公告\" content=\"公告,是公开宣告。\" /><row pubtime=\"2016-04-13 16:36:50\" author=\"网站\" id=\"138\" title=\"12345678\" content=\"12345678\" /><row pubtime=\"2016-04-06 15:02:44\" author=\"网站\" id=\"134\" title=\"关于网站用户注册流程说明1\" content=\"关于用户注册流程说明\" /><row pubtime=\"2016-03-30 18:32:13\" author=\"APP\" id=\"126\" title=\"关于网站使用说明\" content=\"测试\" /><row pubtime=\"2016-03-30 18:29:26\" author=\"网站\" id=\"125\" title=\"关于手机App使用说明\" content=\"123\" /></results>";
}
public static <T> List createList(Class<T> clz ,Results results) throws Exception{
List list = new ArrayList();
for(Row row :results.getRows()){
//根据class和Row生成对象放入list
list.add(createObject(clz,row));
}
return list;
}
public static <T> T createObject(Class<T> clazz ,Row row) throws Exception{
//初始化对象
T obj = clazz.newInstance();
//遍历Info类中所有方法
for (Method method : clazz.getDeclaredMethods()) {
String methodName = method.getName();
Class[] perams = method.getParameterTypes();
//找到set开头,长度大于3,并且入参数量为1的方法
if (methodName.startsWith("set") && methodName.length() > 3 && perams.length == 1) {
String temp = methodName.substring(3, methodName.length());
//拿到属性名称
String fieldName = temp.toLowerCase();
//根据属性名称从HashMap中拿到对应的值
String value = row.get(fieldName);
if(value != null){
//拿到该方法入参的Class,根据入参类型来决定调用方法形式
Class paramClass = perams[0];
if (String.class.equals(paramClass)) {
method.invoke(obj, value);
} else if (Integer.class.equals(paramClass) || int.class.equals(paramClass)) {
method.invoke(obj, Integer.valueOf(value));
} else if (Long.class.equals(paramClass) || long.class.equals(paramClass)) { 下载
method.invoke(obj, Long.valueOf(value));
} else if (BigDecimal.class.equals(paramClass)) {
method.invoke(obj, new BigDecimal(value));
} else if (Boolean.class.equals(paramClass) || boolean.class.equals(paramClass)) {
if(value.equals("true")||value.equals("TRUE"))
method.invoke(obj, true);
if(value.equals("false")||value.equals("FALSE"))
method.invoke(obj, false);
}
}
}
}
return obj;
}
}
最后是输出效果:
Java代码
Info [author=APP, content=公告,是公开宣告。, id=140, pubtime=2016-04-13 16:40:13, title=什么是公告]
Info [author=网站, content=12345678, id=138, pubtime=2016-04-13 16:36:50, title=12345678]
Info [author=网站, content=关于用户注册流程说明, id=134, pubtime=2016-04-06 15:02:44, title=关于网站用户注册流程说明1]
Info [author=APP, content=测试, id=126, pubtime=2016-03-30 18:32:13, title=关于网站使用说明]
Info [author=网站, content=123, id=125, pubtime=2016-03-30 18:29:26, title=关于手机App使用说明]
XStream解析XML文本并用反射机制转换为对象