Springboot三部曲之Controller统一返回ResponseData<T>

在使用Springboot作为工程选型技术的时候，由于其三大特性的自动装配，使得我们把注意力更多的放在功能代码实现上，同时也对代码的编写质量提出了更高的要求，这里所说的质量，说的是编码规范。接下来的我会分为三个步骤去了解整个编码基础构建的要点，Controller统一返回、Controller请求AOP日志管理、Controller统一异常处理。

为什么需要统一返回数据？如果你和你的同时合作过，他来开发后端接口，你来开发前端界面，我想在交互的时候，你会有多么期待统一返回，这会让你的请求变得无比得清秀。下面是一些非统一返回得实例：

@RestController
@RequestMapping("example")
public class ExampleController {

    @GetMapping("str")
    public String str() {
        return "Result Type is String";
    }

    @GetMapping("map")
    @ResponseBody
    public Map<String, Object> map() {
        Map<String, Object> hashMap = new HashMap<>(1);
        hashMap.put("Result", "Map");
        return hashMap;
    }

    @PostMapping("none")
    public void none() {
        System.out.println("none");
    }


}

无论是什么请求，后端人员要是按照自己得喜好或者便利去返回对应得数据，对于前端得请求来说是灾难性得，对前端来说相当不友好。

下面是统一返回实力：

@RestController
@RequestMapping("gua")
public class GuaController {
    @GetMapping("str")
    public ResponseData str() {
        return ResponseDataUtil.buildSuccess("Result String");
    }

    @GetMapping("data")
    public ResponseData data() {
        return ResponseDataUtil.buildSuccess(new User());
    }


    @GetMapping("map")
    public ResponseData map() {
        HashMap<String, Object> map = new HashMap<>(1);
        map.put("Result", "Map");
        return ResponseDataUtil.buildSuccess(map);
    }


}

结果：

{"code":"0000","msg":"Result String","data":null}
{"code":"0000","msg":"请求成功","data":{"name":"DongGua","age":18}}
{"code":"0000","msg":"请求成功","data":{"Result":"Map"}}

前端童鞋可以通过code得约定来处理结果。同样得后端同学也可一写出更加简洁易懂得代码。
ResponseData作为统一返回得实体，由ResponseData作为容器把消息返回。其结构也超级简单，需要三个组件：

ResponseData ResponseDataUtils ResultEnum

下面分别给出其结构：
ResponseData

public class ResponseData<T> implements Serializable {

    private String code;

    private String msg;

    private T data;


    public ResponseData(String code, String msg, T data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    public ResponseData(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public ResponseData(ResultEnums resultEnums) {
        this.code = resultEnums.getCode();
        this.msg = resultEnums.getMsg();
    }

    public ResponseData(ResultEnums resultEnums, T data) {
        this.code = resultEnums.getCode();
        this.msg = resultEnums.getMsg();
        this.data = data;
    }

    public ResponseData() {
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }
}

ResponsDataUtils

public class ResponseDataUtil {
    /**
     * 带实体的统一返回
     *
     * @param data 实体
     * @param <T>  实体类型
     * @return
     */
    public static <T> ResponseData buildSuccess(T data) {
        return new ResponseData<T>(ResultEnums.SUCCESS, data);
    }

    public static ResponseData buildSuccess() {
        return new ResponseData(ResultEnums.SUCCESS);
    }

    public static ResponseData buildSuccess(String msg) {
        return new ResponseData(ResultEnums.SUCCESS.getCode(), msg);
    }

    public static ResponseData buildSuccess(String code, String msg) {
        return new ResponseData(code, msg);
    }

    public static <T> ResponseData buildSuccess(String code, String msg, T data) {
        return new ResponseData<T>(code, msg, data);
    }

    public static ResponseData buildSuccess(ResultEnums resultEnums) {
        return new ResponseData(resultEnums);
    }

    public static <T> ResponseData buildError(T data) {
        return new ResponseData<T>(ResultEnums.ERROR, data);
    }

    public static ResponseData buildError() {
        return new ResponseData(ResultEnums.ERROR);
    }

    public static ResponseData buildError(String msg) {
        return new ResponseData(ResultEnums.ERROR.getCode(), msg);
    }

    public static ResponseData buildError(String code, String msg) {
        return new ResponseData(code, msg);
    }

    public static <T> ResponseData buildError(String code, String msg, T data) {
        return new ResponseData<T>(code, msg, data);
    }

    public static ResponseData buildError(ResultEnums resultEnums) {
        return new ResponseData(resultEnums);
    }
}

ResultEnum

public enum ResultEnums {

    SUCCESS("0000", "请求成功"),
    ERROR("1111", "请求失败"),
    SYSTEM_ERROR("1000", "系统异常"),
    BUSSINESS_ERROR("2001", "业务逻辑错误"),
    VERIFY_CODE_ERROR("2002", "业务参数错误"),
    PARAM_ERROR("2002", "业务参数错误");

    private String code;
    private String msg;

    ResultEnums(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

controller的统一返回实现很简单，但是作用去很大，喜欢的小伙伴可以试着改造以一下自己的工程哟。明天见。