优化后端post请求逻辑

用户名和手机号分开单独检查，细分业务逻辑
错误提示更清晰

api-interface/itmk-base-parent/itmk-base-web/src/main/java/com/itmk/web/user/controller/SysUserController.java

@@ -22,18 +22,25 @@ public class SysUserController {
 
 //    新增用户
     @PostMapping//使用post请求
-    public ResultVo addUser(@RequestBody SysUser sysUser){
-//        判断用户是否重复
-        QueryWrapper<SysUser> queryWrapper = new QueryWrapper<>();
-        queryWrapper.lambda().eq(SysUser::getUsername,sysUser.getUsername()).eq(SysUser::getPhone,sysUser.getPhone());
-        SysUser user = sysUserService.getOne(queryWrapper);
-        if(user != null){
-            return ResultUtils.error("用户已存在！或该手机号已被使用！");
+    public ResultVo addUser(@RequestBody SysUser sysUser) {
+        // 1. 单独检查用户名
+        if (sysUserService.lambdaQuery()
+                .eq(SysUser::getUsername, sysUser.getUsername())
+                .exists()) {
+            return ResultUtils.error("用户名已存在！");
         }
-        if(sysUserService.save(sysUser)){
-            return ResultUtils.success("新增用户成功！");
+
+        // 2. 单独检查手机号
+        if (sysUserService.lambdaQuery()
+                .eq(SysUser::getPhone, sysUser.getPhone())
+                .exists()) {
+            return ResultUtils.error("手机号已被使用！");
         }
-        return ResultUtils.error("新增用户失败！");
+
+        // 3. 保存用户
+        return sysUserService.save(sysUser)
+                ? ResultUtils.success("新增用户成功！")
+                : ResultUtils.error("新增用户失败！");
     }
 
 //    编辑用户