Hi. I have made a springboot api which have a post-method that takes in a list of users as request body, but when I try the api it returns 500 internal server error and it tells me that Jackson cannot find default contructor.
#Spring boot post method returning http 500 because of jackson
lone cloud
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wooden widget
Do you have a default constructor?
lone cloud
yes ive tried to make a default constructor and ive tried labeling everything with jsonProperty and jsonCreator, but i get the same error
Might it have something to do with version conflicts or that they lie in seperate modules or somethiong?
wooden widget
Let me see the class and the endpoint
quick gazelleBOT
@JsonProperty("username")
private String username;
@JsonProperty("balance")
private int balance;
@JsonProperty("password")
private String password;
@JsonCreator
public User() {
}
// Constructor for a new user with a default balance of 1000
@JsonIgnore
public User(String username, String password) {
this(username, 1000, password);
}
// Constructor for a user with a custom balance
@JsonCreator
public User(@JsonProperty("username") String username, @JsonProperty("balance") int balance,
@JsonProperty("password") String password) {
if (balance < 0) {
throw new IllegalArgumentException("Balance cannot be negative");
}
if (username == null || username.isEmpty() || password == null || password.isEmpty()) {
throw new IllegalArgumentException("Username or password is empty");
}
this.username = username;
this.balance = balance;
this.password = password;
}
@JsonProperty("username")
public String getUsername() {
return username;
}
@JsonProperty("password")
public String getPassword() {
return password;
}
@JsonProperty("balance")
public int getBalance() {
return balance;
}
@JsonProperty("username")
public void setUsername(String username) {
this.username = username;
}
@JsonProperty("balance")
public void setBalance(int balance) {
this.balance = balance;
}
@JsonProperty("password")
public void setPassword(String password) {
this.password = password;
}} ```Endpoint: @PostMapping("/saveUsers") public ResponseEntity<String> saveUsers(@RequestBody List<User> users) { if (users == null) { return ResponseEntity.badRequest().body("Users is null"); } users.forEach(user -> { this.createUserFile(user); }); return ResponseEntity.status(HttpStatus.CREATED).body("Users saved"); }
String filePath = this.getJsonFilePath(false, user.getUsername());
File file = new File(filePath);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try (FileWriter writer = new FileWriter(filePath);) {
String jsonUser = new Gson().toJson(user);
writer.write(jsonUser);
} catch (IOException e) {
e.printStackTrace();
}
} ```Do you see the code?
wooden widget
Does the error message say that User does not have a default constructor?
lone cloud
I found the error 🙂