创建从任何自定义对象类型创建 csv 字符串的方法 - 通用

Question

是否可以创建方法来循环任何自定义对象类型的列表，然后从中构建一个 csv 字符串？

到目前为止，我有一个这样的方法签名：

loopData(List<T> records){

}

然后我想循环对象中的每个字段，而不必指定对象类型。

到目前为止，这就是我所看到的，但它似乎明确说明了对象类型，如 ClassABC 中所示：

ClassABC abc = new ClassABC();//!!explicitly stating custom object type!!!

for (Field field : abc.getClass().getDeclaredFields()) {

    field.setAccessible(true);

    String name = field.getName();

    Object value = field.get(abc);

    System.out.printf("%s: %s%n", name, value);

}

有什么办法可以做到这一点？循环每个字段而不明确说明对象类型？

像这样的东西怎么样：

for(T o : records){

            for(Field field:o.getClass().getDeclaredFields()) {

                field.setAccessible(true);

                String name = field.getName();

               Object value = null;

               try {

                   value = field.get(o);

               } catch (IllegalArgumentException | IllegalAccessException e) {

                   // TODO Auto-generated catch block

                   e.printStackTrace();

               }

               System.out.printf("%s: %s%n", name, value);

            }

}

这个循环是否一致？它会每次都以相同的顺序循环对象字段吗？

Answer 1

最后，这就是有效的...我可以获取字段名称并将它们发送给 DOMO 以进行创建，如下所示：&nbsp; &nbsp; List<Column> domoColumns = new ArrayList<Column>();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; for(Field field:o.getClass().getDeclaredFields()) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; field.setAccessible(true);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; String name = field.getName();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; domoColumns.add(new Column(ColumnType.STRING,name));&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }return domoColumns;然后我像这样创建 CSV：StringBuilder stringBuilder = new StringBuilder();&nbsp; &nbsp; for (T o : records) {&nbsp; &nbsp; &nbsp; &nbsp; int numberOfFields = o.getClass().getDeclaredFields().length;&nbsp; &nbsp; &nbsp; &nbsp; int counter = 1;&nbsp; &nbsp; &nbsp; &nbsp; Field[] f = o.getClass().getDeclaredFields();&nbsp; &nbsp; &nbsp; &nbsp; for (int i = 0; i < o.getClass().getDeclaredFields().length; i++) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; f[i].setAccessible(true);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Object value = null;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; try {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value = f[i].get(o);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (counter < numberOfFields) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; stringBuilder.append("\"").append(value).append("\"").append(",");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; stringBuilder.append("\"").append(value).append("\"").append(System.getProperty("line.separator"));&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } catch (IllegalArgumentException | IllegalAccessException e) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // TODO Auto-generated catch block&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e.printStackTrace();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; counter++;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }