[解决方案] spring-mvc 400错误解决办法

先让我们看一下错误信息

HTTP Status 400 -
type Status report

message

description The request sent by the client was syntactically incorrect.

Apache Tomcat/7.0.47

@PathVariable 导致400的错误代码

/**
* @author lvgo
* @version 1.0
* @Description: 调试400错误
* @date 2018/1/17 14:44
*/
@Controller
public class ItemController {

Logger log = Logger.getLogger(ItemController.class);

@Autowired
private ItemService itemService;

@RequestMapping("/item/{itemId}")
@ResponseBody
public TbItem getItemById(@PathVariable Long id) {
TbItem tbItem = itemService.findById(id);
return tbItem;
}
}

修改后代码

/**
* @author lvgo
* @version 1.0
* @Description: 调试400错误
* @date 2018/1/17 14:44
*/
@Controller
public class ItemController {

Logger log = Logger.getLogger(ItemController.class);

@Autowired
private ItemService itemService;

//错误写法
@RequestMapping("/item/{itemId}")
@ResponseBody
public TbItem getItemById(@PathVariable Long id) {
TbItem tbItem = itemService.findById(id);
return tbItem;
}

// 如果使用了@PathVariable注解就一定要遵守注解规则
// 方法参数要么与路径参数相同,要么自定义value值为路径的对应值

// 正确写法1
@RequestMapping("/item/{itemId}")
@ResponseBody
public TbItem getItemById(@PathVariable(value="itemId") Long id) {
TbItem tbItem = itemService.findById(id);
return tbItem;
}

// 正确写法2
@RequestMapping("/item/{itemId}")
@ResponseBody
public TbItem getItemById(@PathVariable Long itemId) {
TbItem tbItem = itemService.findById(itemId);
return tbItem;
}

}

@RequestParam 导致400的正确写法

/**
* @author lvgo
* @version 1.0
* @Description: 调试400错误
* @date 2018/1/17 14:44
*/
@Controller
public class ItemController {

Logger log = Logger.getLogger(ItemController.class);

@Autowired
private ItemService itemService;

// 1.参数必须要传入 name = id
@RequestMapping("/item")
@ResponseBody
public TbItem getItemById(@RequestParam Long id) {
TbItem tbItem = itemService.findById(id);
return tbItem;
}

// 2.这样参数就必须要是 name = itId
@RequestMapping("/item")
@ResponseBody
public TbItem getItemById(@RequestParam(value = "itId") Long id) {
TbItem tbItem = itemService.findById(id);
return tbItem;
}

// 3.这样是给了参数的默认值
@RequestMapping("/item")
@ResponseBody
public TbItem getItemById(@RequestParam(value = "itId",default = "0") Long id) {
TbItem tbItem = itemService.findById(itemId);
return tbItem;
}

}