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目前项目中需要将XML转换为Map，下面给出了自己的代码实现。请各路大神提供更好的代码实现。
场景：
在项目中需要解析XML文本字符串，需要将XML文本字符串映射为Map格式的对象。
需求：
1、为了提高性能，需要使用Stax进行解析
2、Map结构内部需要支持List、Map、String三种数据格式
示例：
例一：
* 字符串：<name>BurceLiu</name><age>18</age>
* 转换为的Map结构：{age=18, name=BurceLiu}
例二：
* 字符串：<student><name>BurceLiu</name><age>18</age></student>
* 转换为的Map结构：{student={age=18, name=BurceLiu}}
例三：
* 字符串：<student><name>BurceLiu</name><age>18</age></student><student><name>BurceLi</name><age>28</age></student>
* 转换为的Map结构：{student=[{age=18, name=BurceLiu}, {age=28, name=BurceLi}]}
例四：
* 字符串：<students><student><name>BurceLiu</name><age>18</age></student><student><name>BurceLi</name><age>28</age></student></students>
* 转换为的Map结构：{students={student=[{age=18, name=BurceLiu}, {age=28, name=BurceLi}]}}
例五：
* 字符串：<str>str1</str><str>str2</str><str>str3</str>
* 转换为的Map结构：{str=[str1, str2, str3]}
代码实现
定义解析接口，提供2个核心方法
public interface IXMLParser {
/**
* xml格式字符串转换为Map
* @param xml
* @return
*/
public Map<String, Object> parse(String xml);
/**
* 初始化动作
* 可以设置初始化动作，例如根节点名称，
*/
public void init();
}
具体实现类，采用Stax技术实现该方案
package com.juxtapose.xml.parser;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamReader;
/**
* xml字符串解析器实现类.<br>
* xml字符串转换为Map对象.<br>
* 转换后的数据类型为Map、List、String三种数据类型.<br>
*
* @author burceliu (mailto:jxta.liu@gmail.com)
*/
public class XMLParserStaxImpl implements IXMLParser {
public static final String NODE_ELEMENT_NAME = "root";
public static final String NODE_DEFAULT_VALUE = "";
private String rootName; //根节点
private String defaultNullValue; //节点没有值的情况下默认值
private static XMLInputFactory factory = XMLInputFactory.newInstance();
static {
factory.setProperty(XMLInputFactory.IS_NAMESPACE_AWARE, Boolean.FALSE);
factory.setProperty(XMLInputFactory.IS_COALESCING, Boolean.TRUE);
}
/* (non-Javadoc)
* @see com.juxtapose.xml.parser.IXMLParser#parse(java.lang.String)
*/
public Map<String, Object> parse(String xml) {
Map<String, Object> map = new HashMap<String, Object>();
StringReader stringReader = null;
try{
stringReader = new StringReader(xml);
XMLStreamReader reader = factory.createXMLStreamReader(stringReader);
map = parse(reader);
}catch(Throwable t){
throw new RuntimeException(t);
}finally{
if(null != stringReader){
try {
stringReader.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
return map;
}
/* (non-Javadoc)
* @see com.juxtapose.xml.parser.IXMLParser#init()
*/
public void init() {
if(this.getRootName() == null){
this.setRootName(NODE_ELEMENT_NAME);
this.setDefaultNullValue(NODE_DEFAULT_VALUE);
}
}
@SuppressWarnings({ "unchecked", "rawtypes" })
private Map<String, Object> parse(XMLStreamReader reader) throws Throwable{
Map<String, Object> map = new HashMap<String, Object>();
Map<String, Object> currentMap = map;
int event = reader.getEventType();
List<String> names = new ArrayList<String>();
NodeAmount nodeAmount = new NodeAmount();
int taglength = 0;
String tagName = null;
String tagValue = this.defaultNullValue;
while(true){
switch (event) {
case XMLStreamConstants.START_DOCUMENT:
break;
case XMLStreamConstants.START_ELEMENT:
tagValue = this.defaultNullValue;
tagName = reader.getLocalName();
if(this.rootName.equals(tagName)){
break;
}
names.add(tagName);
taglength++;
currentMap = map;
if(taglength > 1){
for(int i=0;i< taglength-1;i++){
Object object = currentMap.get(names.get(i));
if(null == object){
object = new HashMap<String, Object>();
currentMap.put(names.get(i), object);
currentMap = (Map<String, Object>)object;
}else{
int currentTagNameSize = nodeAmount.getSize(i + 1 + "" + names.get(i));
if( currentTagNameSize > 1){
if(object instanceof Map){
List parentList = new ArrayList();
parentList.add(object);
Map tempMap = new HashMap();
parentList.add(tempMap);
currentMap.put(names.get(i), parentList);
currentMap = tempMap;
}else if(object instanceof List){
List parentList = (List)object;
int parentListSize = parentList.size();
if(parentListSize != currentTagNameSize){
Map tempMap = new HashMap();
parentList.add(tempMap);
currentMap = tempMap;
}else{
Map tempMap = (Map) parentList.get(parentList.size()-1);
currentMap = tempMap;
}
}
}else{
currentMap = (Map<String, Object>)object;
}
}
}
}
nodeAmount.add(names.size() + tagName);
break;
case XMLStreamConstants.CHARACTERS:
tagValue = reader.getText();
break;
case XMLStreamConstants.END_ELEMENT:
tagName = reader.getLocalName();
if(this.rootName.equals(tagName)){
break;
}
currentMap = map;
if(taglength > 1){
for(int i=0;i< taglength-1;i++){
Object object = currentMap.get(names.get(i));
if(null == object){
//nothing to do
}else{
if(object instanceof List){
List list = (List)object;
currentMap = (Map)list.get(list.size() -1);
}else if(object instanceof Map){
currentMap = (Map)object;
}
}
}
}
Object oldValue = currentMap.get(tagName);
if(!currentMap.containsKey(tagName)){
currentMap.put(tagName, tagValue);
nodeAmount.remove(names.size() + tagName);
}else{
if(oldValue instanceof List){
List list = (List)oldValue;
if(list.size() > 0){
Object obj = list.get(0);
if(obj instanceof String){
((List)oldValue).add(tagValue);
nodeAmount.remove(names.size() + tagName);
}
}
}else if(oldValue instanceof Map){
}else{
List tmpList = new ArrayList();
currentMap.put(tagName, tmpList);
tmpList.add(oldValue);
tmpList.add(tagValue);
nodeAmount.remove(names.size() + tagName);
}
}
tagValue = this.defaultNullValue;
names.remove(names.size()-1);
taglength--;
break;
case XMLStreamConstants.END_DOCUMENT:
break;
}
if (!reader.hasNext()) {
break;
}
event = reader.next();
}
return map;
}
public String getRootName() {
return rootName;
}
public void setRootName(String rootName) {
this.rootName = rootName;
}
public String getDefaultNullValue() {
return defaultNullValue;
}
public void setDefaultNullValue(String defaultNullValue) {
this.defaultNullValue = defaultNullValue;
}
class NodeAmount{
private Map<String, AtomicInteger> map =new HashMap<String, AtomicInteger>();
public void add(String nodeName){
AtomicInteger integer = map.get(nodeName);
if(null == integer){
integer = new AtomicInteger(0);
map.put(nodeName, integer);
}
integer.incrementAndGet();
}
public void remove(String nodeName){
AtomicInteger integer = map.get(nodeName);
if(null != integer){
integer.decrementAndGet();
}
}
public int getSize(String nodeName){
AtomicInteger integer = map.get(nodeName);
if(null == integer){
integer = new AtomicInteger(0);
map.put(nodeName, integer);
}
return integer.intValue();
}
}
}
/*
* 修改历史
* $Log$
*/
单元测试：
package test.com.juxtapose.xml.parser;
import java.util.Map;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import com.juxtapose.xml.parser.IXMLParser;
import com.juxtapose.xml.parser.XMLParserStaxImpl;
/**
*
* @author burceliu (mailto:jxta.liu@gmail.com)
*/
public class TestXMLParserStaxImpl {
/**
* @throws java.lang.Exception
*/
@BeforeClass
public static void setUpBeforeClass() throws Exception {
}
/**
* @throws java.lang.Exception
*/
@AfterClass
public static void tearDownAfterClass() throws Exception {
}
/**
* @throws java.lang.Exception
*/
@Before
public void setUp() throws Exception {
}
/**
* @throws java.lang.Exception
*/
@After
public void tearDown() throws Exception {
}
@Test
public void test() {
IXMLParser parser = new XMLParserStaxImpl();
parser.init();
String xml = "<root><student><name>BurceLiu</name><age>18</age></student></root>";
Map<String, Object> result = parser.parse(xml);
System.out.println(result);
xml = "<root><student><name>BurceLiu</name><age>18</age></student><student><name>BurceLi</name><age>28</age></student></root>";
result = parser.parse(xml);
System.out.println(result);
xml = "<root><str>str1</str><str>str2</str><str>str3</str></root>";
result = parser.parse(xml);
System.out.println(result);
xml = "<root><students><student><name>BurceLiu</name><age>18</age></student><student><name>BurceLi</name><age>28</age></student></students></root>";
result = parser.parse(xml);
System.out.println(result);
xml = "<root><name>BurceLiu</name><age>18</age></root>";
result = parser.parse(xml);
System.out.println(result);
}
}
/*
* 修改历史
* $Log$
*/
观察控制台的输出结果：
{student={age=18, name=BurceLiu}}
{student=[{age=18, name=BurceLiu}, {age=28, name=BurceLi}]}
{str=[str1, str2, str3]}
{students={student=[{age=18, name=BurceLiu}, {age=28, name=BurceLi}]}}
{age=18, name=BurceLiu}
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原文地址：http://www.cnblogs.com/jxta/p/4283107.html
