Java对象转JSON字符串实用类：字段映射与格式化

// 将对象转换成json字符串
public String toJSON(Object obj) {
if (obj != null) {
Class c = obj.getClass();
String className = c.getName();
HashMap<String, String> map = new HashMap<String, String>();
Field[] fields = c.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
String name = fields[i].getName();
try {
fields[i].setAccessible(true);
Object o = fields[i].get(obj);
if (o instanceof Number) {
map.put("\"" + name + "\"", o.toString());
} else if (o instanceof String) {
map.put("\"" + name + "\"", "\"" + o.toString() + "\"");
}
} catch (IllegalArgumentException e) {
Log.e("info", "error:" + e.toString());
} catch (IllegalAccessException e) {
Log.e("info", "error:" + e.toString());
}
}
map.put("\"" + "class" + "\"", className);
String s = map.toString();
String str = s.replaceAll("\"=", "\":");
Log.d("info", str);
return str;
} else {
Toast.makeText(context, "对不起，您操作有误", Toast.LENGTH_SHORT).show();