如何遍历具有地图作为jstl中的字段的对象列表？

Question

我有一个类 Spravochnik，它有一个字段 HashMap。如何使用 jstl 对其进行迭代？我想要一个jsp页面给我看表。Spravochnik 映射将列名映射到给定表的列对象（列数可能因表而异）。这是我在控制器中的方法。

 @RequestMapping(value = "/list")

  public String getSpravochniks(Model m, @RequestParam String tableName)

  {

    List<Spravochnik> spravList =

        spravochnikService.findAll(tableName);

    m.addAttribute("spravList", spravList);

    return "list";

  }

当我有如下所示的 jsp 时，它显示错误属性限定名称必须在元素内是唯一的（id 是超类 Spravochnik 继承的字段

  <c:forEach var="sprav" items="${spravList}">

            <tr>

                <td>

                    ${sprav.id}

                </td>

                <td>

                    ${sprav.map}

                </td>

            </tr>

        </c:forEach>

Spravochnik.class

public class Spravochnik extends BaseEntity {

    private HashMap<String, Object> map;

    public HashMap<String, Object> getMap() {

        return map;

    }

    public void setMap(HashMap<String, Object> map) {

        this.map = map;

    }  

}

也可能是 SpravochnikRowMapper

public class SpravochnikRowMapper implements RowMapper<Spravochnik> {

    @Override

    public Spravochnik mapRow(ResultSet rs, int arg1) throws SQLException {

        Spravochnik spr = new Spravochnik();

        ResultSetMetaData rsmeta = rs.getMetaData();

        HashMap<String, Object> map = new HashMap<>();

        int columnCount = rsmeta.getColumnCount();

        for(int column = 1; column <= columnCount; column++){

            map.put(rsmeta.getColumnName(column),rs.getObject(column));

        }

        return spr;

    }

}

Answer 1

我认为你也必须迭代 map （map类的字段Spravochnik）。也许是这样：&nbsp;<c:forEach var="sprav" items="${spravList}">&nbsp; &nbsp; &nbsp; &nbsp; <tr>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ${sprav.id}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <c:forEach items="${sprav.map}" var="entry">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Key = ${entry.key}, value = ${entry.value}<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </c:forEach>&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </td>&nbsp; &nbsp; &nbsp; &nbsp; </tr>&nbsp; &nbsp; </c:forEach>&nbsp; &nbsp; 我认为你也必须迭代 map （map类的字段Spravochnik）。也许是这样：&nbsp;<c:forEach var="sprav" items="${spravList}">&nbsp; &nbsp; &nbsp; &nbsp; <tr>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ${sprav.id}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <c:forEach items="${sprav.map}" var="entry">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Key = ${entry.key}, value = ${entry.value}<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </c:forEach>&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </td>&nbsp; &nbsp; &nbsp; &nbsp; </tr>&nbsp; &nbsp; </c:forEach>&nbsp; &nbsp;&nbsp;