refactor: 重构neo4j服务

backend/internal/handler/node_handler.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	"github.com/gin-gonic/gin"
+	"knowledge-graph-backend/internal/model"
 	"knowledge-graph-backend/internal/service"
 )
 
@@ -29,19 +30,13 @@ func NewNodeHandler(svc service.GraphService) *NodeHandler {
 func (h *NodeHandler) GetNodeByID(c *gin.Context) {
 	nodeID := c.Param("id")
 	if nodeID == "" {
-		c.JSON(http.StatusBadRequest, gin.H{
-			"error":   "Bad Request",
-			"message": "Node ID is required",
-		})
+		c.JSON(http.StatusBadRequest, model.ErrorResponse{Error: "bad_request", Message: "Node ID is required"})
 		return
 	}
 
 	node, found := h.service.GetNodeByID(nodeID)
 	if !found {
-		c.JSON(http.StatusNotFound, gin.H{
-			"error":   "Not Found",
-			"message": "Node with ID '" + nodeID + "' not found",
-		})
+		c.JSON(http.StatusNotFound, model.ErrorResponse{Error: "not_found", Message: "Node with ID '" + nodeID + "' not found"})
 		return
 	}
 
@@ -60,19 +55,13 @@ func (h *NodeHandler) GetNodeByID(c *gin.Context) {
 func (h *NodeHandler) GetNeighbors(c *gin.Context) {
 	nodeID := c.Param("id")
 	if nodeID == "" {
-		c.JSON(http.StatusBadRequest, gin.H{
-			"error":   "Bad Request",
-			"message": "Node ID is required",
-		})
+		c.JSON(http.StatusBadRequest, model.ErrorResponse{Error: "bad_request", Message: "Node ID is required"})
 		return
 	}
 
 	neighbors, found := h.service.GetNeighbors(nodeID)
 	if !found {
-		c.JSON(http.StatusNotFound, gin.H{
-			"error":   "Not Found",
-			"message": "Node with ID '" + nodeID + "' not found",
-		})
+		c.JSON(http.StatusNotFound, model.ErrorResponse{Error: "not_found", Message: "Node with ID '" + nodeID + "' not found"})
 		return
 	}