【Java后端封装数据】常见后端封装数据的格式，用于返回给前端使用（109）

数据格式一：包装 List Map 返回，常用于数据展示；

	// Controller：
	public Result selectRegConfig(@RequestBody String param) {
        try {
            Map<String, Object> paramMap = JsonUtils.readValue(param, Map.class);
            return Result.success().result(xxxListService.selectRegConfig(paramMap));
        } catch (Exception e) {
            log.error("QuestionListController selectRegConfig is error===:" + e.getMessage(), e);
            return Result.failure("查询失败");
        }
    }
    
	// Service:做了分页展示，所以使用PageInfo>接收
	PageInfo<Map<String, Object>> selectRegConfig(Map<String, Object> paramMap);
	
	// ServiceImpl
	@Override
    public PageInfo<Map<String, Object>> selectRegConfig(Map<String, Object> paramMap) {
        List<Map<String, Object>> list = xxxListMapper.selectRegConfig(paramMap);
        PageInfo<Map<String, Object>> result = new PageInfo<>(list);
        return result;
    }

数据格式二：包装 对象返回；通过封装POJO对象返回数据；

	// POJO：
	@Data
	public class DataCount {
	    private String total;  // 总数
	    private String closed;  // 已关闭
	}
	
	// Controller：
	public Result getDeclaratData(HttpServletRequest request,@RequestBody String param) {
        try {
            Map<String, Object> paramMap = JsonUtils.readValue(param, Map.class);
            return Result.success().result(xxxListService.getDeclaratData(request,paramMap));
        } catch (Exception e) {
            log.error("QuestionListController getDeclaratData is error===:" + e.getMessage(), e);
            return Result.failure("查询失败");
        }
    }
	
	// Service:
	DataCount getDeclaratData (HttpServletRequest request, Map<String, Object> paramMap);
	
	// ServiceImpl
	@Override
    public DataCount  getDeclaratData(HttpServletRequest request, Map<String, Object> paramMap) {
        DataCount data = new DataCount();
		int total = 0;
		int closed = 0;
        data.setTotal(String.valueOf(total));
        data.setClosed(String.valueOf(closed));
        return data;
    }

数据格式三：包装 Map返回；

	// Controller：
	public Result getRevealData(HttpServletRequest request,@RequestBody String param) {
        try {
            Map<String, Object> paramMap = JsonUtils.readValue(param, Map.class);
            return Result.success().result(xxxListService.getRevealData(request,paramMap));
        } catch (Exception e) {
            log.error("QuestionListController getRevealData is error===:" + e.getMessage(), e);
            return Result.failure("失败");
        }
    }
    
	// Service:
	Map<String, Object> getRevealData (HttpServletRequest request,Map<String, Object> paramMap);
	
	// ServiceImpl
	@Override
    public Map<String, Object> getRevealData (HttpServletRequest request, Map<String, Object> paramMap) {
        Map<String,Object> map = new HashMap<>();
        int A = 0;  
        int B = 0; 
        map.put("A",A);
        map.put("B",B);
        return map;
    }
	

数据格式四：对象，Map，List互相嵌套（随意嵌套封装返回）；
如：
1.对象里面嵌套对象，嵌套List等；
2.Map里面嵌套map，嵌套List等；
3.对象和Map互相嵌套等；
返回可以是：List Map ，对象，Map；

总结：包装对象和包装Map从结果上来看是一样的，就看自己使用习惯！