controller level

method-level

package spittr.web;
import static org.springframework.web.bind.annotation.RequestMethod.*;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller 
public class HomeController {
  @RequestMapping(value="/", method=GET)
  public String home() {
    return "home"; 
  }
}

class-level

@Controller
@RequestMapping("/")  //@RequestMapping({"/", "/homepage"})
public class HomeController {
  @RequestMapping(method=GET)
  public String home() {
    return "home";
    } 
}

passing model data to the view

• 數(shù)據(jù)流： controller --> view resolver --> view
• 數(shù)據(jù)的類型： Model宾符，本質(zhì)上是一個(gè)map
• controller函數(shù)中始終返回的是view 名稱匠抗，Model 數(shù)據(jù)的傳遞由框架來(lái)實(shí)現(xiàn)
• 在前端的jsp中，可以通過(guò)key來(lái)訪問(wèn)數(shù)據(jù)

傳遞模型數(shù)據(jù)的幾種形式

返回view name隙咸， 數(shù)據(jù)保存在model中

• 返回的view名稱"spittles", 傳遞的數(shù)據(jù)保存在Model（map）中
• Model 不明確指定key，默認(rèn)自動(dòng)推導(dǎo)可以為"spittleList"(List<Spittle> 推導(dǎo)而來(lái))

@Controller
@RequestMapping("/spittles")
public class SpittleController {
    private SpittleRepository spittleRepository;
    @Autowired
    public SpittleController(
    SpittleRepository spittleRepository) {
        this.spittleRepository = spittleRepository;
    }
    @RequestMapping(method=RequestMethod.GET)
    public String spittles(Model model) {
      model.addAttribute(spittleRepository.findSpittles(Long.MAX_VALUE, 20));//model.addAttribute("spittleList", spittleRepository.findSpittles(Long.MAX_VALUE, 20));
      return "spittles";
    } 
}

返回view name, 數(shù)據(jù)使用java.util.Map保存

@RequestMapping(method=RequestMethod.GET)
public String spittles(Map model) {
  model.put("spittleList",
          spittleRepository.findSpittles(Long.MAX_VALUE, 20));
  return "spittles";
}

返回?cái)?shù)據(jù)成洗，view name讓框架自動(dòng)推導(dǎo)（最好別這么做）

@RequestMapping(method=RequestMethod.GET)
public List<Spittle> spittles() {
  return spittleRepository.findSpittles(Long.MAX_VALUE, 20));
}

• 返回的數(shù)據(jù)會(huì)保存到Model中五督，Model key也是自動(dòng)推導(dǎo)
• view name 根據(jù)request path推到而來(lái)， 比例：http://xxx/spittles, view name就是spittles

request input

獲取參數(shù)

@RequestMapping(method=RequestMethod.GET)
public List<Spittle> spittles(
  @RequestParam(value="max", defaultValue=MAX_LONG_AS_STRING) long max,
  @RequestParam(value="count", defaultValue="20") int count) {
  return spittleRepository.findSpittles(max, count);
}

resource-orientation 資源化的url

  @RequestMapping(value="/{spittleId}", method=RequestMethod.GET)
  public String spittle(
      @PathVariable("spittleId") long spittleId, 
      Model model) {
    model.addAttribute(spittleRepository.findOne(spittleId));
    return "spittle";
  }

• @PathVariable 可以省略參數(shù)瓶殃，默認(rèn)和函數(shù)的參數(shù)相同充包， 即spittleId (long spittleId)

processing forms

form controller

@RequestMapping(value="/register", method=POST)
public String processRegistration(Spitter spitter) {
    spitterRepository.save(spitter);
    return "redirect:/spitter/" +
           spitter.getUsername();
}

validating forms

import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

public class SpittleForm {

  @NotNull
  @Size(min=1, max=140)
  private String message;
  
  @Min(-180)
  @Max(180)
  private Double longitude;
  
  @Min(-90)
  @Max(90)
  private Double latitude;
  .....
}

• controller 對(duì)應(yīng)的處理函數(shù)中必須增加一個(gè)org.springframework.validation.Errors 參數(shù)

  @RequestMapping(value="/register", method=POST)
  public String processRegistration(
      @Valid Spitter spitter, 
      Errors errors) {
    if (errors.hasErrors()) {
      return "registerForm";
    }
    
    spitterRepository.save(spitter);
    return "redirect:/spitter/" + spitter.getUsername();
  }