JSON 字符串 与 java 对象的转换

// 引入相应的包

//json-lib-2.2-jdk15.jar

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

1. //把java 对象列表转换为json对象数组，并转为字符串

    JSONArray array = JSONArray.fromObject(userlist);     String jsonstr = array.toString();

2.//把java对象转换成json对象，并转化为字符串

  JSONObject object = JSONObject.fromObject(invite);   Log4jInit.ysulogger.debug(object.toString());

3.//把JSON字符串转换为JAVA 对象数组

  String personstr = getRequest().getParameter("persons");   JSONArray json = JSONArray.fromObject(personstr);   List<InvoidPerson> persons = (List<InvoidPerson>)JSONArray.toCollection(json, nvoidPerson.class); 4.//把JSON字符串转换为JAVA 对象

  str = "{\"lendperson\":\"李四\",\"lendcompany\":\"有限公司\",\"checkperson\":\"李四\",   \"lenddate\":\"2010-07-19T00:00:00\",\"lendcounts\":4,\"   passports\":[{\"passportid\":\"d\",\"name\":\"李豫川\",\"passporttype\":\"K\"},   {\"passportid\":\"K9051\",\"name\":\"李平\",\"passporttype\":\"K\"},   {\"passportid\":\"K90517\",\"name\":\"袁寒梅\",\"passporttype\":\"K\"},   {\"passportid\":\"K905199\",\"name\":\"贺明\",\"passporttype\":\"K\"}]}";    JSONObject jsonobject = JSONObject.fromObject(str);   PassportLendsEntity passportlends = null;   try {    //获取一个json数组    JSONArray array = jsonobject.getJSONArray("passports");    //将json数组 转换成 List<PassPortForLendsEntity>泛型    List<PassPortForLendsEntity> list = new ArrayList<PassPortForLendsEntity>();    for (int i = 0; i < array.size(); i++) {                JSONObject object = (JSONObject)array.get(i);               PassPortForLendsEntity passport = (PassPortForLendsEntity)JSONObject.toBean(object,               PassPortForLendsEntity.class);             if(passport != null){              list.add(passport);             }            }    //转换PassportLendsEntity 实体类    passportlends = (PassportLendsEntity)JSONObject.toBean(jsonobject, PassportLendsEntity.class);