java生成json常见问题总结

Json必备包
commons-beanutils-1.7.0.jar不加这个包
java.lang.NoClassDefFoundError: org/apache/commons/beanutils/DynaBean

commons-collections-3.2.jar 不加这个包
java.lang.NoClassDefFoundError: org/apache/commons/collections/map/ListOrderedMap

commons-lang-2.3.jar不加这个包
java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException

commons-logging-1.0.4.jar不加这个包
java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory

ezmorph-1.0.6.jar不加这个包
java.lang.NoClassDefFoundError: net/sf/ezmorph/Morpher
（本人亲测，没有这个包，myeclipse不抛异常，跟踪执行到JSONObject jsonObj = JSONObject.fromObject(jsonMap);这段代码就中断了，其以后的代码也不执行了，确实没有像网上说的不抛异常）

json-lib-2.1-jdk15.jar不加这个包
java.lang.NoClassDefFoundError: net/sf/json/JSONObject

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

public class JsonUtil {
public void listToJson() {
List<Object> jsonList = new ArrayList<Object>();
jsonList.add("nihao");
jsonList.add("hello");
jsonList.add("haha");
jsonList.add("heihei");

JSONArray jsonArray = JSONArray.fromObject(jsonList);
System.out.println(jsonArray);
}
//输出结果：["nihao","hello","haha","heihei"]

public void mapToJson() {
Map<Object, Object> jsonMap = new HashMap<Object, Object>();
jsonMap.put("name", "Ren");
jsonMap.put("sex", "man");
jsonMap.put("age", 24);

JSONObject jsonObject = JSONObject.fromObject(jsonMap);
System.out.println(jsonObject);
}

//输出结果：{"sex":"man","name":"Ren","age":24}

public void mapAndListToJson() {
JSONArray jsonArr = new JSONArray();
JSONObject jsonObj = new JSONObject();

for(int i = 0; i < 10; i++) {
JSONObject tjo = new JSONObject();
tjo.put("optValue", i+"");
tjo.put("optText", i+"Text");
jsonArr.add(tjo);
}
jsonObj.put("options", jsonArr);
System.out.println(jsonObj);
}

输出结果：

{"options":[{"optValue":"0","optText":"0Text"},{"optValue":"1","optText":"1Text"},{"optValue":"2","optText":"2Text"},{"optValue":"3","optText":"3Text"},{"optValue":"4","optText":"4Text"},{"optValue":"5","optText":"5Text"},{"optValue":"6","optText":"6Text"},{"optValue":"7","optText":"7Text"},{"optValue":"8","optText":"8Text"},{"optValue":"9","optText":"9Text"}]}}