java web业务中经常用常量来表示不同的 HTTP 响应状态,比如

public enum AppHttpCodeEnum {// 成功段0SUCCESS(200,"操作成功"),// 登录段1~50NEED_LOGIN(1,"需要登录后操作"),LOGIN_PASSWORD_ERROR(2,"密码错误"),// TOKEN50~100TOKEN_INVALID(50,"无效的TOKEN"),TOKEN_EXPIRE(51,"TOKEN已过期"),TOKEN_REQUIRE(52,"TOKEN是必须的"),// SIGN验签 100~120SIGN_INVALID(100,"无效的SIGN"),SIG_TIMEOUT(101,"SIGN已过期"),// 参数错误 500~1000PARAM_REQUIRE(500,"缺少参数"),PARAM_INVALID(501,"无效参数"),PARAM_IMAGE_FORMAT_ERROR(502,"图片格式有误"),SERVER_ERROR(503,"服务器内部错误"),// 数据错误 1000~2000DATA_EXIST(1000,"数据已经存在"),AP_USER_DATA_NOT_EXIST(1001,"ApUser数据不存在"),DATA_NOT_EXIST(1002,"数据不存在"),// 数据错误 3000~3500NO_OPERATOR_AUTH(3000,"无权限操作"),NEED_ADMIND(3001,"需要管理员权限");int code;String errorMessage;AppHttpCodeEnum(int code, String errorMessage){this.code = code;this.errorMessage = errorMessage;}public int getCode() {return code;}public String getErrorMessage() {return errorMessage;}
}

这种枚举的使用方式允许你在代码中使用这些常量来表示不同的 HTTP 响应状态，而不需要硬编码状态码和错误消息。这提高了代码的可读性和可维护性，并降低了错误的风险，因为你可以使用这些常量而不是手动输入状态码和消息。例如，你可以使用 AppHttpCodeEnum.SUCCESS.getCode() 来获取成功状态码，使用 AppHttpCodeEnum.SUCCESS.getErrorMessage() 来获取成功消息。并且无需要,实列化,直接写常量就会在加载服务的时候实列化，这个枚举类型 AppHttpCodeEnum 中定义的枚举常量是可以直接使用的，不需要创建新的枚举对象，就像使用静态变量一样

一般配合响应类来进行使用

public class ResponseResult<T> implements Serializable {private String host;private Integer code;private String errorMessage;private T data;public ResponseResult() {this.code = 200;}public ResponseResult(Integer code, T data) {this.code = code;this.data = data;}public ResponseResult(Integer code, String msg, T data) {this.code = code;this.errorMessage = msg;this.data = data;}public ResponseResult(Integer code, String msg) {this.code = code;this.errorMessage = msg;}public static ResponseResult errorResult(int code, String msg) {ResponseResult result = new ResponseResult();return result.error(code, msg);}public static ResponseResult okResult(int code, String msg) {ResponseResult result = new ResponseResult();return result.ok(code, null, msg);}public static ResponseResult okResult(Object data) {ResponseResult result = setAppHttpCodeEnum(AppHttpCodeEnum.SUCCESS, AppHttpCodeEnum.SUCCESS.getErrorMessage());if(data!=null) {result.setData(data);}return result;}public static ResponseResult errorResult(AppHttpCodeEnum enums){return setAppHttpCodeEnum(enums,enums.getErrorMessage());}public static ResponseResult errorResult(AppHttpCodeEnum enums, String errorMessage){return setAppHttpCodeEnum(enums,errorMessage);}public static ResponseResult setAppHttpCodeEnum(AppHttpCodeEnum enums){return okResult(enums.getCode(),enums.getErrorMessage());}private static ResponseResult setAppHttpCodeEnum(AppHttpCodeEnum enums, String errorMessage){return okResult(enums.getCode(),errorMessage);}public ResponseResult<?> error(Integer code, String msg) {this.code = code;this.errorMessage = msg;return this;}public ResponseResult<?> ok(Integer code, T data) {this.code = code;this.data = data;return this;}public ResponseResult<?> ok(Integer code, T data, String msg) {this.code = code;this.data = data;this.errorMessage = msg;return this;}public ResponseResult<?> ok(T data) {this.data = data;return this;}public Integer getCode() {return code;}public void setCode(Integer code) {this.code = code;}public String getErrorMessage() {return errorMessage;}public void setErrorMessage(String errorMessage) {this.errorMessage = errorMessage;}public T getData() {return data;}public void setData(T data) {this.data = data;}public String getHost() {return host;}public void setHost(String host) {this.host = host;}
}