Question

我正在做一个小型的春季项目，当我尝试显示数据迭代resultList时，我遇到了一个问题，结果列表被设置并且foreach循环超过4次作为项目，但是给出了异常，经过我意识到项目是retrive但是如果它们只是Object而不是porper cast class这是因为当我尝试调用getUrl（）方法时崩溃（如果我调用toString工作正常）。

是控制器

 @RequestMapping(value = "/search", method = RequestMethod.GET)
 public ModelAndView home(ModelMap model,@RequestParam(required=false,value="") String name) {

        List<Result> result = googleSearchService.doSearch(name);
        modelAndView.addObject("resultList",result);//<- after debub list is full of Result items
        return modelAndView;
}

视图

<c:forEach items="${resultList}" var="item">
            <li><c:out value="${item.getUrl()}"/></li>  
        </c:forEach>

结果类是一个内部类：

public class GoogleResults {


private ResponseData responseData;

public ResponseData getResponseData() {
    return responseData;
}

public void setResponseData(ResponseData responseData) {
    this.responseData = responseData;
}

public String toString() {
    return "ResponseData[" + responseData + "]";
}



static class ResponseData {

    private List<Result> results;

    public List<Result> getResults() {
        return results;
    }

    public void setResults(List<Result> results) {
        this.results = results;
    }

    public String toString() {
        return "Results[" + results + "]";
    }
}


static class Result {

    public String url;

    private String title;

    public String getUrl() {
        return url;
    }

    public String getTitle() {
        return title;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String toString() {
        return "Result[url:" + url + ",title:" + title + "]";
    }
  }
}

跟踪：

ava.lang.NullPointerException javax.el.BeanELResolver.invoke（BeanELResolver.java:159） org.apache.jasper.el.JasperELResolver.invoke（JasperELResolver.java:147） org.apache.el.parser.AstValue.getValue（AstValue.java:157） org.apache.el.ValueExpressionImpl.getValue（ValueExpressionImpl.java:187）

Answer 1

课程Result应标记为public

弹簧

1 个答案: