JSon数据的解析

最近一个项目要对艺龙,携程等酒店预订网站进行价格信息采集.因为这两个网站都不是省油的灯啊,多次提交ajax表单,参数编码,获取特定的城市和酒店代码等等手段,可谓过五关斩六将,总算是把数据采集回来,但是又面临一个难题:采集回来的信息是json格式的,那就涉及到json数据转换成java对象了

首先要了解json数据的格式

[{"CityType":"hotel","TabList":[{"TabId":"1","Name":"\u70ED\u95E8","NameEn":"Hot","CityList":[{"ProvinceId":null,"CityId":"0101","CityCode":"0101","CityNameCn":"\u5317\u4EAC","CityNameEn":"Beijing","CityThreeSign":"","CityType":"hotel","OldEnglishName":"peking"},{"ProvinceId":null,"CityId":"0201","CityCode":"0201","CityNameCn":"\u4E0A\u6D77","CityNameEn":"Shanghai","CityThreeSign":"","CityType":"hotel","OldEnglishName":""},{"ProvinceId":null,"CityId":"2001","CityCode":"2001","CityNameCn":"\u5E7F\u5DDE","CityNameEn":"Guangzhou","CityThreeSign":"","CityType":"hotel","OldEnglishName":"canton"}]}]}];

jsonViewer是个好东西,不过HTTPAnalysis直接就集成了jsonViewer,不过还是前者比较轻巧:

json和java之间的互换可以使用json-lib, 基本的使用可以看文档就行.网上也有一些集成的类,我建议直接看它的源代码,了解他是如何通过反射和使用临时对象解析json数据,并封装成java对象.

这个json数据时list的嵌套,如果要对整个json文件解析,需要使用如下方法,需要构造跟json数据对应的Tab.class 和City.class,而且字段名称必须一致(骆驼首字母小写),提供默认构造方法,这样就可以将json数据作为一个完整的对象,想怎么干都行了.

HashMap<String,Class> map = new HashMap<String,Class>();
map.put("tabList", Tab.class);
map.put("cityList", City.class);

/**
* 从一个JSON数组得到一个java对象集合，其中对象中包含有集合属性
* @param object
* @param clazz
* @param map 集合属性的类型 (key : 集合属性名, value : 集合属性类型class) eg: ("beansList" : Bean.class)
* @return
*/
public static List getDTOList(String jsonString, Class clazz, Map map){
setDataFormat2JAVA();
JSONArray array = JSONArray.fromObject(jsonString);
List list = new ArrayList();
for(Iterator iter = array.iterator(); iter.hasNext();){
JSONObject jsonObject = (JSONObject)iter.next();
list.add(JSONObject.toBean(jsonObject, clazz, map));
}
return list;
}

由于我的需求只是需要重json数据中获取特定的信息对象,如上面的cityList,像tabList等对象我没必要去构造和获取,而且在实际使用过程中我发现

json数据中变量如果不是首字母小写,是无法转换成java对象的.这个确实很坑爹!!!!!

于是乎,我就写了个直接读取和解析一个片段json数据的类,有了这个类,加上对象映射,基本上没什么解析不了

package com.gxy.weixin.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class JSonStrUtils {

/**
* json 数据括号自动补全
* **/
public static String autoComplete(String targetJson) {
LinkedList<Character> stack = new LinkedList<Character>();
String returnStr = "";
char[] charArray = targetJson.toCharArray();
for (int i = 0; i < charArray.length; i++) {
if (charArray[i] == '[' || charArray[i] == '{') {// 入栈
stack.addFirst(charArray[i]);
} else if (charArray[i] == ']') {
// 判断是否闭合
char last = stack.peekFirst();
if (last != '[') {// 不闭合,补 }
returnStr += '}';
} else// 闭合
{
stack.pollFirst();
}
} else if (charArray[i] == '}') {
// 判断是否闭合
char last = stack.peekFirst();
if (last != '{') {// 不闭合,补 }
returnStr += ']';
} else// 闭合
{
stack.pollFirst();
}
}
returnStr += charArray[i];
}
for (char c : stack) {
System.out.println("left in stack:" + c);
}
return returnStr;
}

/***
* 用于处理json数据中出现变量名非首字母小写的情况,利用正则匹配变量,然后把首字母变成小写
* */
public static String dealWithFirstChar(String jsonInput) {
String originalInput = jsonInput;
StringBuilder inputStr = new StringBuilder(jsonInput);
String regex = "\"(\\w+)\":";
Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher(inputStr);
List<String> result = new ArrayList<String>();
while (m.find()) {
String valueName = m.group(1);
String newValueName = null;
char[] words = valueName.toCharArray();
if (Character.isUpperCase(words[0])) {// 首字母大写,不符合变量命名规范

words[0] = Character.toLowerCase(words[0]);
newValueName = new String(words);
// System.out.println("orignal value:"+valueName+" new value :"+
// newValueName);
// String regexWord = "\""+valueName+"\":";
String regx1 = "\"" + valueName + "\":";
String replace = "\"" + newValueName + "\":";
originalInput = originalInput.replaceAll(regx1, replace);
}
result.add(valueName);
inputStr.delete(0, m.end(0));
m = p.matcher(inputStr);
}
return originalInput;

}

/***
* 用户将unicode编码转换成汉字
* */
public static String UnicodeToString(String str) {
Pattern pattern = Pattern.compile("(\\\\u(\\p{XDigit}{4}))");
Matcher matcher = pattern.matcher(str);
char ch;
while (matcher.find()) {
ch = (char) Integer.parseInt(matcher.group(2), 16);
str = str.replace(matcher.group(1), ch + "");
}
return str;
}

/***
* 用户将汉字转换成unicode编码
* */
public static String toUNICODE(String s) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) <= 256) {
sb.append("\\u00");
} else {
sb.append("\\u");
}
sb.append(Integer.toHexString(s.charAt(i)).toUpperCase());
}
return sb.toString();
}

/**
* 读取json文件,转换为字符串
* */
public static String readJSonFile(String fileName) {
InputStream in = null;
String jsonStr = "";
try {
in = JSonStrUtils.class.getResourceAsStream(fileName);
BufferedReader reader = new BufferedReader(
new InputStreamReader(in));
String temp = reader.readLine();
while (temp != null) {
jsonStr += temp;
temp = reader.readLine();
}
in.close();
} catch (IOException e) {
e.printStackTrace();
System.out.println("read json file failed :" + fileName);
}
return jsonStr;
}

/***
* 在指定的JSONObject 中寻找特定属性的第一个值
* */
public static List<String> findTargetProperty(JSONObject object,
String propertyName, boolean isRecursive) {
List<String> values = new ArrayList<String>();
for (Iterator entries = object.names().iterator(); entries.hasNext();) {
String name = (String) entries.next();
Object value = object.get(name);
if (name.equals(propertyName)) {// 找到目标属性
values.add(value.toString());
} else if (isRecursive) {
if (value instanceof JSONObject) {
values.addAll(findTargetProperty((JSONObject) value,
propertyName, isRecursive));
} else if (value instanceof JSONArray) {
JSONArray array = (JSONArray) value;
for (Iterator iter = array.iterator(); iter.hasNext();) {
JSONObject jsonObject = (JSONObject) iter.next();
values.addAll(findTargetProperty(jsonObject,
propertyName, isRecursive));
}
}
}
}
return values;
}

/***
* 从指定的JSonArray中寻找指定名称的子json数组
* */
public static List<JSONArray> findTargetJSonArray(JSONArray array,
String targetName) {
List<JSONArray> arrays = new ArrayList<JSONArray>();
for (Iterator iter = array.iterator(); iter.hasNext();) {// 遍历数组中的JSONObject
JSONObject jsonObject = (JSONObject) iter.next();
if (jsonObject == null || jsonObject.isNullObject()) {
continue;
}
for (Iterator entries = jsonObject.names().iterator(); entries
.hasNext();) {
String name = (String) entries.next();
Object value = jsonObject.get(name);
if (value instanceof JSONArray) {// 属性为数组
// 先判断是否目标数组
if (name.equals(targetName)) {
arrays.add((JSONArray) value);
}
// 递归查找
arrays.addAll(findTargetJSonArray((JSONArray) value,
targetName));
}
}
}
return arrays;

}
}

原文地址：http://xoknight.net/?cat=58