java查询将其保存在列表中<String>持久性jpql

Question

我必须实现这个方法

public List<String> getAuthorArticlesPercentageForCategory (String categoryText) {
    /* in this query i count the articles in a spesific category*/
    Query q=em.createQuery("SELECT COUNT(ar) FROM Article ar WHERE ar.categoryId.categoryText=:categoryText")
    .setParameter("categoryText", categoryText);
    Long n=(Long)q.getSingleResult();   
    /* in this query i found the authors and count the articles which they wrote in the spesific category */  
    Query  w=em.createQuery( "SELECT ar.authorId.firstName,count(ar) FROM Article ar WHERE ar.categoryId.categoryText=:categoryText GROUP BY ar.authorId"); 
    w.setParameter("categoryText", categoryText); 
    List list1=w.getResultList();  
    /*stop here i cant go on*/
    return list;

这个列表必须返回一个List<String>，格式如下：

name: (ar.authorId.firstName) , category(categoryname), percent (这必须是 count(ar) from 2query/n)

Answer 1

你使用一个实体管理器对象。所以返回一个列表，使用 q.getresultlist()。 然后迭代 for(String str:list1) 等。