JSON中optString和getString方法的区别

 /**   * Returns the value mapped by {@code name} if it exists, coercing it if   * necessary, or throws if no such mapping exists.   *   * @throws JSONException if no such mapping exists.   */  public String getString(String name) throws JSONException {    Object object = get(name);    String result = JSON.toString(object);    if (result == null) {      throw JSON.typeMismatch(name, object, "String");    }    return result;  }  /**   * Returns the value mapped by {@code name} if it exists, coercing it if   * necessary, or the empty string if no such mapping exists.   */  public String optString(String name) {    return optString(name, "");  }