init: 2026Technology-Competition initial commit

backend/ims-common/src/main/java/com/ims/common/constant/ResultCode.java

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+package com.ims.common.constant;
+
+import lombok.Getter;
+
+@Getter
+public enum ResultCode {
+    SUCCESS(200, "success"),
+    BAD_REQUEST(400, "bad request"),
+    UNAUTHORIZED(401, "unauthorized"),
+    FORBIDDEN(403, "forbidden"),
+    NOT_FOUND(404, "not found"),
+    INTERNAL_ERROR(500, "internal server error"),
+    BUSINESS_ERROR(1001, "business error");
+
+    private final int code;
+    private final String message;
+
+    ResultCode(int code, String message) {
+        this.code = code;
+        this.message = message;
+    }
+}

backend/ims-common/src/main/java/com/ims/common/dto/ApiResponse.java

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+package com.ims.common.dto;
+
+import com.ims.common.constant.ResultCode;
+import lombok.Data;
+
+import java.time.LocalDateTime;
+
+@Data
+public class ApiResponse<T> {
+    private int code;
+    private String message;
+    private T data;
+    private String timestamp;
+
+    public ApiResponse() {
+        this.timestamp = LocalDateTime.now().toString();
+    }
+
+    public static <T> ApiResponse<T> success(T data) {
+        ApiResponse<T> response = new ApiResponse<>();
+        response.setCode(ResultCode.SUCCESS.getCode());
+        response.setMessage(ResultCode.SUCCESS.getMessage());
+        response.setData(data);
+        return response;
+    }
+
+    public static <T> ApiResponse<T> error(int code, String message) {
+        ApiResponse<T> response = new ApiResponse<>();
+        response.setCode(code);
+        response.setMessage(message);
+        return response;
+    }
+
+    public static <T> ApiResponse<T> error(ResultCode resultCode) {
+        return error(resultCode.getCode(), resultCode.getMessage());
+    }
+}

backend/ims-common/src/main/java/com/ims/common/dto/PageResult.java

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+package com.ims.common.dto;
+
+import lombok.Data;
+import java.util.Collections;
+import java.util.List;
+
+@Data
+public class PageResult<T> {
+    private List<T> items;
+    private long total;
+    private int page;
+    private int pageSize;
+    private int totalPages;
+
+    public PageResult() {
+        this.items = Collections.emptyList();
+    }
+
+    public PageResult(List<T> items, long total, int page, int pageSize) {
+        this.items = items;
+        this.total = total;
+        this.page = page;
+        this.pageSize = pageSize;
+        this.totalPages = pageSize > 0 ? (int) Math.ceil((double) total / pageSize) : 0;
+    }
+}

backend/ims-common/src/main/java/com/ims/common/exception/BusinessException.java

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+package com.ims.common.exception;
+
+import com.ims.common.constant.ResultCode;
+import lombok.Getter;
+
+@Getter
+public class BusinessException extends RuntimeException {
+    private final int code;
+
+    public BusinessException(String message) {
+        super(message);
+        this.code = ResultCode.BUSINESS_ERROR.getCode();
+    }
+
+    public BusinessException(int code, String message) {
+        super(message);
+        this.code = code;
+    }
+}

backend/ims-common/src/main/java/com/ims/common/util/JwtUtil.java

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+package com.ims.common.util;
+
+import io.jsonwebtoken.*;
+
+import javax.crypto.SecretKey;
+import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
+import java.util.Date;
+
+public class JwtUtil {
+
+    private final SecretKey key;
+    private final long accessTokenExpiration;
+    private final long refreshTokenExpiration;
+
+    public JwtUtil(String secret, long accessTokenExpiration, long refreshTokenExpiration) {
+        this.key = new SecretKeySpec(secret.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
+        this.accessTokenExpiration = accessTokenExpiration;
+        this.refreshTokenExpiration = refreshTokenExpiration;
+    }
+
+    public String generateAccessToken(Long userId, String username) {
+        return Jwts.builder()
+                .subject(username)
+                .claim("userId", userId)
+                .issuedAt(new Date())
+                .expiration(new Date(System.currentTimeMillis() + accessTokenExpiration))
+                .signWith(key, Jwts.SIG.HS256)
+                .compact();
+    }
+
+    public String generateRefreshToken(Long userId, String username) {
+        return Jwts.builder()
+                .subject(username)
+                .claim("userId", userId)
+                .issuedAt(new Date())
+                .expiration(new Date(System.currentTimeMillis() + refreshTokenExpiration))
+                .signWith(key, Jwts.SIG.HS256)
+                .compact();
+    }
+
+    public Claims parseToken(String token) {
+        return Jwts.parser()
+                .verifyWith(key)
+                .build()
+                .parseSignedClaims(token)
+                .getPayload();
+    }
+
+    public boolean validateToken(String token) {
+        try {
+            parseToken(token);
+            return true;
+        } catch (JwtException | IllegalArgumentException e) {
+            return false;
+        }
+    }
+}