Breakingbad

React + Spring Boot Developer 🚀
Documenting my backend journey with Java, PostgreSQL & Spring Boot

[Breakingbad @Breakingbad_iv]

long time no post 🫤

[Emmy of Ila @debruyne_12]

Me trying to understand the abbreviations I confidently wrote in my notes weeks ago.

[Breakingbad @Breakingbad_iv]

My Journey of learning backend development

Today: Input Validation + Clean Errors

This is where your API stops being naïve and starts being safe.

Never trust client input. Ever. Here's what I learned

#LearnInPublic #100DaysOfCode

[Breakingbad @Breakingbad_iv]

My API now has:

- Consistent response structure
- Global exception handling
- Input validation with clean errors

Follow along if you're on the same journey

#SpringBoot #Java #LearnInPublic

[Breakingbad @Breakingbad_iv]

My Journey of learning backend development

Today: Input Validation + Clean Errors

This is where your API stops being naïve and starts being safe.

Never trust client input. Ever. Here's what I learned

#LearnInPublic #100DaysOfCode

[Breakingbad @Breakingbad_iv]

Why validate at the DTO level, not inside the service?

Because the service shouldn't care about malformed input that's not its job. DTOs are the boundary between the outside world and your system. Keep concerns separated. One layer, one responsibility.

[Drax📿 @Bigdraxxx7]

See billionaire daughter head and you wey your papa no guide dey find 700k wig😭

[Cyber_Racheal @CyberRacheal]

😭🤣

[kaizen @kumxem]

Small account happiness ✊😭

[Breakingbad @Breakingbad_iv]

Common mistakes I learned to avoid:

- Mixing raw responses with ApiResponse
- Catching exceptions inside the service layer
- Returning stack traces to the frontend

Stack traces are for logs. Never for clients.

[Breakingbad @Breakingbad_iv]

The fix: a universal ApiResponse<T> wrapper.

Every response , success or error — now looks the same:

{ "success": true, "data": { ... } }
{ "success": "false", "message": "User not found" }

Frontend devs can actually rely on this.

[Breakingbad @Breakingbad_iv]

The Solutiion: @RestControllerAdvice + @ExceptionHandler annotation

One class catches ALL exceptions thrown anywhere in your app.

Service throws → Spring catches → handler returns clean JSON.

Controller stays clean. Service stays clean.

[Breakingbad @Breakingbad_iv]

Up next: validation error handling + proper HTTP status

#SpringBoot #Java #LearnInPublic

[Breakingbad @Breakingbad_iv]

Why handle exceptions globally instead of in each controller?

Because duplicating try/catch everywhere is:
– Error-prone
– Hard to keep consistent

One handler = one source of truth. Change it once, and it works everywhere.

[Breakingbad @Breakingbad_iv]

Common mistakes I learned to avoid:

- Mixing raw responses with ApiResponse
- Catching exceptions inside the service layer
- Returning stack traces to the frontend

Stack traces are for logs. Never for clients.

[Breakingbad @Breakingbad_iv]

Why handle exceptions globally instead of in each controller?

Because duplicating try/catch everywhere is:
– Error-prone
– Hard to keep consistent

One handler = one source of truth. Change it once, and it works everywhere.

[Breakingbad @Breakingbad_iv]

Why handle exceptions globally instead of in each controller?

Because duplicating try/catch everywhere is:
– Error-prone
– Hard to keep consistent

One handler = one source of truth. Change it once, and it works everywhere.

[Breakingbad @Breakingbad_iv]

The Solutiion: @RestControllerAdvice + @ExceptionHandler annotation

One class catches ALL exceptions thrown anywhere in your app.

Service throws → Spring catches → handler returns clean JSON.

Controller stays clean. Service stays clean.

[Breakingbad @Breakingbad_iv]

The Solutiion: @RestControllerAdvice + @ExceptionHandler annotation

One class catches ALL exceptions thrown anywhere in your app.

Service throws → Spring catches → handler returns clean JSON.

Controller stays clean. Service stays clean.

[Breakingbad @Breakingbad_iv]

The fix: a universal ApiResponse<T> wrapper.

Every response , success or error — now looks the same:

{ "success": true, "data": { ... } }
{ "success": "false", "message": "User not found" }

Frontend devs can actually rely on this.