java处理json的工具类(list,map和json的之间的转换)

需要下载第三方的jar ：net.sf.json

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import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections.map.ListOrderedMap;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
/**
*
* 处理json的工具类.
* <br>本类为处理json的工具类
* @author slj
*/
public class JsonTools {

/**
*
* json转换list.
* <br>详细说明
* @param jsonStr json字符串
* @return
* @return List<Map<String,Object>> list
* @throws
* @author slj
* @date 2013年12月24日 下午1:08:03
*/
public static List<Map<String, Object>> parseJSON2List(String jsonStr){
JSONArray jsonArr = JSONArray.fromObject(jsonStr);
List<Map<String, Object>> list = new ArrayList<Map<String,Object>>();
Iterator<JSONObject> it = jsonArr.iterator();
while(it.hasNext()){
JSONObject json2 = it.next();
list.add(parseJSON2Map(json2.toString()));
}
return list;
}

/**
*
* json转换map.
* <br>详细说明
* @param jsonStr json字符串
* @return
* @return Map<String,Object> 集合
* @throws
* @author slj
*/
public static Map<String, Object> parseJSON2Map(String jsonStr){
ListOrderedMap map = new ListOrderedMap();
//最外层解析
JSONObject json = JSONObject.fromObject(jsonStr);
for(Object k : json.keySet()){
Object v = json.get(k);
//如果内层还是数组的话，继续解析
if(v instanceof JSONArray){
List<Map<String, Object>> list = new ArrayList<Map<String,Object>>();
Iterator<JSONObject> it = ((JSONArray)v).iterator();
while(it.hasNext()){
JSONObject json2 = it.next();
list.add(parseJSON2Map(json2.toString()));
}
map.put(k.toString(), list);
} else {
map.put(k.toString(), v);
}
}
return map;
}

/**
*
* 通过HTTP获取JSON数据.
* <br>通过HTTP获取JSON数据返回list
* @param url 链接
* @return
* @return List<Map<String,Object>> list
* @throws
* @author slj
*/
public static List<Map<String, Object>> getListByUrl(String url){
try {
//通过HTTP获取JSON数据
InputStream in = new URL(url).openStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder sb = new StringBuilder();
String line;
while((line=reader.readLine())!=null){
sb.append(line);
}
return parseJSON2List(sb.toString());
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

/**
*
* 通过HTTP获取JSON数据.
* <br>通过HTTP获取JSON数据返回map
* @param url 链接
* @return
* @return Map<String,Object> 集合
* @throws
* @author slj
*/
public static Map<String, Object> getMapByUrl(String url){
try {
//通过HTTP获取JSON数据
InputStream in = new URL(url).openStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder sb = new StringBuilder();
String line;
while((line=reader.readLine())!=null){
sb.append(line);
}
return parseJSON2Map(sb.toString());
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
*
* map转换json.
* <br>详细说明
* @param map 集合
* @return
* @return String json字符串
* @throws
* @author slj
*/
public static String mapToJson(Map<String, String> map) {
Set<String> keys = map.keySet();
String key = "";
String value = "";
StringBuffer jsonBuffer = new StringBuffer();
jsonBuffer.append("{");
for (Iterator<String> it = keys.iterator(); it.hasNext();) {
key = (String) it.next();
value = map.get(key);
jsonBuffer.append(key + ":" +"""+ value+""");
if (it.hasNext()) {
jsonBuffer.append(",");
}
}
jsonBuffer.append("}");
return jsonBuffer.toString();
}

//test
public static void main(String[] args) {
String url = "http://...";
List<Map<String,Object>> list = getListByUrl(url);
System.out.println(list);
}
}