如何在Controller中编写例程并使用URL映射它。浏览URL，它应该会显示结果

Question

方法在大学中增加。java模型类

公共静态列表列表CollegesForCity（String pCity）{back entityManager（）. createQuery（"SELECT o From College o WHEREo.addressInfoId.city=？1"，College.class）. setParameter（1， pCity）. getResultList（）；}

public static List<College> listColleges(String pCity, String pState, String pCountry) {
    return entityManager().createQuery("SELECT o from College o WHERE o.addressInfoId.city=?1 AND (?2 IS null or o.addressInfoId.state=?2) AND (?3 IS null OR o.addressInfoId.country=?3)", College.class)
            .setParameter(1, pCity)
            .setParameter(2, pState)
            .setParameter(3, pCountry)
            .getResultList();
}

public static List<College> listColleges(String pCity, String pState, String pCountry, int pFirstResults, int pMaxResults) {
    return entityManager().createQuery(" ", College.class)
            .setParameter(1, pCity)
            .setParameter(2, pState)
            .setParameter(3, pCountry)
            .setFirstResult(pFirstResults)
            .setMaxResults(pMaxResults)
            .getResultList();
}

public static long countColleges(String pCity, String pState, String pCountry) {
    return entityManager().createQuery("SELECT COUNT(o) from College o WHERE o.addressInfoId.city=?1 AND (?2 IS null or o.addressInfoId.state=?2) AND (?3 IS null OR o.addressInfoId.country=?3)", Long.class)
            .setParameter(1, pCity)
            .setParameter(2, pState)
            .setParameter(3, pCountry)
            .getSingleResult();
}

}

这是我在collegeController.java的例行公事

//http://localhost:8080/college/colleges/find?city=pune

@RequestMapping(value="/find", method = RequestMethod.GET)
public String findCollegeForCity(Model uiModel, @RequestParam(value = "city", required = true) String pCity,
       @RequestParam(value = "country", required = false) String pCountry,
       @RequestParam(value = "state", required = false) String pState,
       @RequestParam(value = "page", required = false) Integer page,
       @RequestParam(value = "size", required = false) Integer size) {
    if (page != null || size != null) {
        int sizeNo = size == null ? 10 : size.intValue();
        final int firstResult = page == null ? 0 : (page.intValue() - 1) * sizeNo;
        uiModel.addAttribute("colleges", College.listColleges(pCity, pState, pCountry, firstResult, sizeNo));
        float nrOfPages = (float) College.countColleges(pCity, pState, pCountry) / sizeNo;
        uiModel.addAttribute("maxPages", (int) ((nrOfPages > (int) nrOfPages || nrOfPages == 0.0) ? nrOfPages + 1 : nrOfPages));
    } else {
        uiModel.addAttribute("colleges", College.listColleges(pCity, pState, pCountry));
    }
    return "colleges/list";
}

}

Answer 1

我认为您的方法签名中缺少一个< code > @ path variable String city :

@RequestMapping(value="/{city}",params = { "find=city", "form" }, method = RequestMethod.GET) 
public String findCollegeForCity(Model uiModel, @PathVariable String city) { 
   uiModel.addAttribute("colleges", College.listCollegesForCity(city)); 
   return "colleges/find"; 
}