Spring统一（分页）返回结果（新）

背景

在分布式、微服务盛行的今天，绝大部分项目都采用的微服务框架，前后端分离方式。前端和后端进行交互，
前端按照约定请求URL路径，并传入相关参数，后端服务器接收请求，进行业务处理，返回数据给前端。

设计

• 返回代码的一般格式

{
     
	# 是否响应成功
	success: true,
	# 响应状态码
	code: 200,		
	# 响应数据
	data: Object
	# 返回错误信息
	message: "",
}

分析

• code：响应状态码

code区间	类型	含义
1**	100-199	信息 服务器接收到请求，需要请求者继续执行操作
2**	200-299	成功 请求被成功接收并处理
3**	300-399	重定向 需要进一步的操作以完成请求
4**	400-499	客户端错误 请求包含语法错误或无法完成请求
5**	500-599	服务器错误 服务器在处理的时候发生错误

• 常见的HTTP状态码：

    200 - 请求成功；
    301 - 资源（网页等）被永久转移到其它URL；
    404 - 请求的资源（网页等）不存在；
    500 - 内部服务器错误。
  

统一返回结果

@Getter
public enum ResultCodeEnum {
     
    SUCCESS(true, 200,"成功"),
    ERROR(false, 500,"失败"),
    UNKNOWN_REASON(false, 20001, "未知错误"),
    BAD_SQL_GRAMMAR(false, 21001, "sql语法错误"),
    JSON_PARSE_ERROR(false, 21002, "json解析异常"),
    PARAM_ERROR(false, 21003, "参数不正确"),
    FILE_UPLOAD_ERROR(false, 21004, "文件上传错误"),
    EXCEL_DATA_IMPORT_ERROR(false, 21005, "Excel数据导入错误");
    private Boolean type;

    private Integer code;

    private String message;

    private ResultCodeEnum(Boolean type, Integer code, String message) {
     
        this.type = type;
        this.code = code;
        this.message = message;
    }
}

@Data
@ApiModel(value = "全局统一返回结果")
public class Result<T> implements Serializable {
     

    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = "是否成功")
    private Boolean state = true;

    @ApiModelProperty(value = "返回数据")
    private T data;

    @ApiModelProperty(value = "返回消息")
    private String msg;

    @ApiModelProperty(value = "返回的数据总数")
    private long count;

    @ApiModelProperty(value = "返回码")
    private long code;

    public Result() {
     

    }

    Result(long code, boolean success, String message, long count, T data) {
     
        this.code = code;
        this.state = success;
        this.msg = message;
        this.data = data;
        this.count = count;
    }

    public static <T> Result<T> ok(T data) {
     
        try {
     
            Result<T> result = new Result<T>(ResultCodeEnum.SUCCESS.getCode(), ResultCodeEnum.SUCCESS.getType(), ResultCodeEnum.SUCCESS.getMessage(), 1, data);

            return result;
        } catch (Exception ex) {
     
            return error(ex);
        }
    }

    public static <T> Result<T> error(Exception ex) {
     
        String format = "Message: %s, StackTrace: %s, Suppressed: %s, Cause: %s, Class: %s ";

        String msg = String.format(format, ex.getMessage(), ex.getStackTrace(), ex.getSuppressed(),
                ex.getCause(), ex.getClass());

        return error(msg);
    }

    public static <T> Result<T> error(String message) {
     
        Result<T> result = new Result<T>( ResultCodeEnum.ERROR.getCode(), ResultCodeEnum.ERROR.getType(), message, 0, null);
        result.count = 0;
        return result;
    }
}

统一分页返回结果

• 传参

@Data
public class PagingOptions implements Serializable {
     

    private static final long serialVersionUID = 1L;

    @ApiModelProperty("当前页数")
    private Integer pageIndex;
    @ApiModelProperty("每页条数")
    private Integer pageSize;
    @ApiModelProperty("查询条件")
    private List<PagingSort> sorts;
    @ApiModelProperty("排序条件")
    private List<PagingFilter> filters;

}

@Data
public class PagingFilter implements Serializable {
     

    private static final long serialVersionUID = 1L;

    @ApiModelProperty("数据库字段")
    private String field;
    @ApiModelProperty("条件")
    private String op;
    @ApiModelProperty("值")
    private String value;

}

@Data
public class PagingSort implements Serializable {
     

    private static final long serialVersionUID = 1L;

    @ApiModelProperty("数据库字段")
    private String field;
    @ApiModelProperty("条件")
    private String sort;

}

• 封装mybatisPlus

@Data
public class PageQuery<T>  {
     
    private static final long serialVersionUID = 1L;

    /**
     * 分页的条件
     */
    private Page<T> page;
    /**
     * 当前页数
     */
    private int currPage = 1;
    /**
     * 每页条数
     */
    private int limit = 10;

    private QueryWrapper<T> queryWrapper;

    private BaseMapper baseMapper;


    public PageQuery(PagingOptions pagingOptions, BaseMapper baseMapper) {
     
        this.baseMapper = baseMapper;
        // 分页的参数
        this.page = new Page<>(pagingOptions.getPageIndex(), pagingOptions.getPageSize());

        //将每个类的mapper进行赋值
        this.queryWrapper = new QueryWrapper<T>();

        //组装wrapper的条件
        if (pagingOptions.getFilters() != null) {
     
            for (PagingFilter filter : pagingOptions.getFilters()) {
     

                if (StringUtils.isEmpty(filter.getField()) || StringUtils.isEmpty(filter.getOp())) {
     
                    continue;
                }

                String strOp = filter.getOp().trim();
                String field = filter.getField().trim();
                String term = filter.getValue();

                switch (strOp) {
     
                    case "eq":
                        this.queryWrapper.eq(field, term);
                        break;
                    case "ne":
                        this.queryWrapper.ne(field, term);
                        break;
                    case "lt":
                        this.queryWrapper.lt(field, term);
                        break;
                    case "le":
                        this.queryWrapper.le(field, term);
                        break;
                    case "gt":
                        this.queryWrapper.gt(field, term);
                        break;
                    case "ge":
                        this.queryWrapper.ge(field, term);
                        break;
                    case "cn":
                        this.queryWrapper.like(field, term);
                        break;
                    case "nu":
                        this.queryWrapper.isNull(field);
                        break;
                    case "nn":
                        this.queryWrapper.isNotNull(field);
                        break;
                    case "in":
                        List<String> result = Arrays.asList(term.split(","));
                        this.queryWrapper.in(field, result);
                        break;
                }

            }
        }

        if (pagingOptions.getSorts() != null) {
     

            for (PagingSort sort : pagingOptions.getSorts()) {
     

                if (StringUtils.isEmpty(sort.getField()) || StringUtils.isEmpty(sort.getSort())) {
     
                    continue;
                }
                String strOp = sort.getSort().trim();

                switch (strOp) {
     
                    case "asc":
                        this.queryWrapper.orderByAsc(sort.getField());
                        break;
                    case "desc":
                        this.queryWrapper.orderByDesc(sort.getField());
                        break;
                }
            }
        }
    }
}

• 统一返回

@Data
@ApiModel(value = "全局统一分页返回结果")
public class PagingResult<T> implements Serializable {
     

    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = "是否成功")
    private Boolean state = true;

    @ApiModelProperty(value = "返回数据")
    private List<T> data;

    @ApiModelProperty(value = "返回消息")
    private String msg;

    @ApiModelProperty(value = "返回的数据总数")
    private long count;

    @ApiModelProperty(value = "返回码")
    private long code;

    PagingResult(long code, boolean success, String message, long count, List<T> data) {
     
        this.setCode(code);
        this.setState(success);
        this.setMsg(message);
        this.setData(data);
        this.setCount(count);
    }

    public static <T> PagingResult<T> ok(PageQuery<T> pageQuery, BaseMapper<T> mapper) {
     
        try {
     

            IPage<T> page = mapper.selectPage(pageQuery.getPage(), pageQuery.getQueryWrapper());

            PagingResult<T> result = new PagingResult<T>(ResultCodeEnum.SUCCESS.getCode(), ResultCodeEnum.SUCCESS.getType(), ResultCodeEnum.SUCCESS.getMessage(),
                    page.getTotal(), page.getRecords());

            return result;
        } catch (Exception ex) {
     
            return error(ex);
        }
    }

    public static <T> PagingResult<T> error(Exception ex) {
     
        String format = "Message: %s, StackTrace: %s, Suppressed: %s, Cause: %s, Class: %s";

        String msg = String.format(format, ex.getMessage(), ex.getStackTrace(), ex.getSuppressed(),
                ex.getCause(), ex.getClass());

        return error(msg);
    }

    public static <T> PagingResult<T> error(String message) {
     
        PagingResult<T> result = new PagingResult<T>(ResultCodeEnum.ERROR.getCode(), ResultCodeEnum.ERROR.getType(), message, 0, null);

        return result;
    }
}