判断字符串string是数字、json结构、xml结构
    import org.json.JSONException;
import org.json.JSONObject;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
public class StringTest {
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		String string1 = "123";
		String string2 = "fdgsewe323";
		String string3 = "{/"task/":/"324vfsdfg/"}";
		String string4 = "<ww>3243</ww>";
//		System.out.println("string1::number"+isNumber(string1));
//		System.out.println("string2::number"+isNumber(string2));
//		System.out.println("string3::json"+isJson(string3));
//		System.out.println("string4::xml"+isXML(string4));
//		System.out.println("string1::json"+isJson(string1));
//		System.out.println("string2::xml"+isXML(string2));
//		System.out.println("string3::number"+isNumber(string3));
//		System.out.println("string4::xml"+isXML(string4));		
		System.out.println("string1::"+getType(string1));
		System.out.println("string2::"+getType(string2));
		System.out.println("string3::"+getType(string3));
		System.out.println("string4::"+getType(string4));
	}	
	public static String getType(String string) {
		if (isNumber(string))
			return "Number";
		else if (isJson(string))
			return "Json";
		else if (isXML(string))
			return "xml";
		else 
			return "String";
	}		
	/** 
	* 判断字符串是否是数字 
	*/ 
	public static boolean isNumber(String value) { 
	return isInteger(value) || isDouble(value); 
	} 
	/** 
	* 判断字符串是否是整数 
	*/ 
	public static boolean isInteger(String value) { 
	try { 
	Integer.parseInt(value); 
	return true; 
	} catch (NumberFormatException e) { 
	return false; 
	} 
	} 
	/** 
	* 判断字符串是否是浮点数 
	*/ 
	public static boolean isDouble(String value) { 
	try { 
	Double.parseDouble(value); 
	if (value.contains(".")) 
	return true; 
	return false; 
	} catch (NumberFormatException e) { 
	return false; 
	} 
	} 	
	/**
	 * 判断是否是json结构
	 */
	public static boolean isJson(String value) {
		try {
			new JSONObject(value);
		} catch (JSONException e) {
			return false;
		}
		return true;
	}	
	/**
	 * 判断是否是xml结构
	 */
	public static boolean isXML(String value) {
		try {
			DocumentHelper.parseText(value);
		} catch (DocumentException e) {
			return false;
		} 
		return true;
	}
}