sax解析xml的特殊字符解决方法

1. 如果特殊字符很少，并且出现在特定的tag里，最简单的方法就是生成xml的时候加入标志“<![CDATA[formula]]>”如，

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>
<Root>
<ITEM>
<AreaID>1</AreaID>
<ParentID>0</ParentID>
<AreaName>0</AreaName>
</ITEM>
<ITEM>
<AreaID>2</AreaID>
<ParentID>1</ParentID>
<AreaName><![CDATA[aaa<bbb?1:2]]></AreaName>
</ITEM>
</Root>

2. 如果不确定哪一个tag会有像<，>等的特殊字符，或者出现特殊字符的tag比较多，则最好使用转义
因为SAX解析判断是否是一个element是通过<>,</>来判断的，所以想大于号、小于号等为了避免混淆，要使用转义

小于号 < <

大于号 > >

与号 & &

单引号 ‘ '

双引号 “ "

比如，

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>
<Root>
<ITEM>
<AreaID>1</AreaID>
<ParentID>0</ParentID>
<AreaName>0</AreaName>
</ITEM>
<ITEM>
<AreaID>2</AreaID>
<ParentID>1</ParentID>
<AreaName>a<b</AreaName>
</ITEM>
</Root>

<AreaName>a<b</AreaName>

解析的时候，sax解析AreaName的时候进入startElement进入一次，会进入characters至少3次(说至少的意思是有些tag中间会有空格或TAB，本例中只会调用3次)，分别会返回”a“, "<", "b",把这三次拼接起来就是我们需要的字串，完整程序如下
package com.kingman.hello.xml;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import android.util.Log;

public class AreaHandler extends DefaultHandler{
private static final String TAG = "AreaHandler";
final int AREA_ID = 1;
final int PARENT_ID = 2;
final int AREA_NAME = 3;
AreaFeed mAreaFeed;
AreaItem mAreaItem;
private int currentstate;
private StringBuffer str = null;

public AreaHandler() {

}

@Override
public void startDocument() throws SAXException {
Log.v(TAG, "startDocument");
mAreaFeed = new AreaFeed();
mAreaItem = new AreaItem();
}

@Override
public void endDocument() throws SAXException {
Log.v(TAG, "endDocument");
}

@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
Log.v(TAG, "startElement");
str = new StringBuffer();
if (localName.equals("ITEM"))
{
mAreaItem = new AreaItem();
return;
}
if (localName.equals("AreaID"))
{
currentstate = AREA_ID;
return;
}
if (localName.equals("ParentID"))
{
currentstate = PARENT_ID;
return;
}
if (localName.equals("AreaName"))
{
currentstate = AREA_NAME;
return;
}
}

@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
Log.v(TAG, "endElement");
super.endElement(uri, localName, qName);
if (localName.equals("ITEM"))
{
mAreaFeed.addItem(mAreaItem);
return;
}
switch (currentstate)
{
case AREA_ID:
mAreaItem.setmAreaID(str.toString());
currentstate = 0;
break;
case PARENT_ID:
mAreaItem.setmParentID(str.toString());
currentstate = 0;
break;
case AREA_NAME:
Log.v(TAG, "AREA_NAME - str = " + str);
mAreaItem.setmAreaName(str.toString());
currentstate = 0;
break;
default:
return;
}

}

@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
String theString = new String(ch,start,length);
str.append(theString);
Log.v(TAG, "str = " + str);
}

public AreaFeed getFeed() {
return mAreaFeed;
}

}

package com.kingman.hello.xml;

import java.io.InputStream;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import com.kingman.hello.R;

public class SAXParseActivity extends Activity{
public final String TAG = "XMLParseActivity";
private AreaFeed feed = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.xml_listview);
feed = getFeed(R.raw.area);
showListView();
}

private AreaFeed getFeed(int r_id) {
try
{
InputStream inputStream = null;

//xml file 放到 assets目录中的
inputStream = getResources().getAssets().open("blog.xml");
//inputStream = openFileInput("blog.xml");

//创建SAX解析工厂
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
XMLReader xmlreader = parser.getXMLReader();
//为XMLReader设置内容处理器
AreaHandler xmlHandler = new AreaHandler();
xmlreader.setContentHandler(xmlHandler);	//设置事件处理函数

InputSource is = new InputSource(inputStream);
//开始解析文件
xmlreader.parse(is);

return xmlHandler.getFeed();
} catch (Exception ee){
return null;
}
}

private void showListView()
{
Log.v(TAG, "showListView");
ListView itemlist = (ListView) findViewById(R.id.itemlist);
if (feed == null)
{
setTitle("Can't display");
return;
}

SimpleAdapter adapter = new SimpleAdapter(this, feed.getAllItemsForListView(),
R.layout.xml_three_textview, new String[] { AreaItem.AREA_ID, AreaItem.PARENT_ID , AreaItem.AREA_NAME},
new int[] { R.id.tv1 , R.id.tv2, R.id.tv3});
itemlist.setAdapter(adapter);
itemlist.setSelection(0);

}
}