Only using @JsonIgnore during serialization, but not deserialization

Question

I have a user object that is sent to and from the server. When I send out the user object, I don't want to send the hashed password to the client. So, I added @JsonIgnore on the password property, but this also blocks it from being deserialized into the password that makes it hard to sign up users when they don't have a password.

How can I only get @JsonIgnore to apply to serialization and not deserialization? I'm using Spring JSONView, so I don't have a ton of control over the ObjectMapper.

Things I've tried:

1. Add @JsonIgnore to the property
2. Add @JsonIgnore on the getter method only

Solution 1

Exactly how to do this depends on the version of Jackson that you're using. This changed around version 1.9, before that, you could do this by adding @JsonIgnore to the getter.

Which you've tried:

Add @JsonIgnore on the getter method only

Do this, and also add a specific @JsonProperty annotation for your JSON "password" field name to the setter method for the password on your object.

More recent versions of Jackson have added READ_ONLY and WRITE_ONLY annotation arguments for JsonProperty. So you could also do something like:

@JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
private String password;

Docs can be found here.

Solution 2

In order to accomplish this, all that we need is two annotations:

1. @JsonIgnore
2. @JsonProperty

Use @JsonIgnore on the class member and its getter, and @JsonProperty on its setter. A sample illustration would help to do this:

class User {

    // More fields here
    @JsonIgnore
    private String password;

    @JsonIgnore
    public String getPassword() {
        return password;
    }

    @JsonProperty
    public void setPassword(final String password) {
        this.password = password;
    }
}

Solution 3

Since version 2.6: a more intuitive way is to use the com.fasterxml.jackson.annotation.JsonProperty annotation on the field:

@JsonProperty(access = Access.WRITE_ONLY)
private String myField;

Even if a getter exists, the field value is excluded from serialization.

JavaDoc says:

/**
 * Access setting that means that the property may only be written (set)
 * for deserialization,
 * but will not be read (get) on serialization, that is, the value of the property
 * is not included in serialization.
 */
WRITE_ONLY

In case you need it the other way around, just use Access.READ_ONLY.

Solution 4

In my case, I have Jackson automatically (de)serializing objects that I return from a Spring MVC controller (I am using @RestController with Spring 4.1.6). I had to use com.fasterxml.jackson.annotation.JsonIgnore instead of org.codehaus.jackson.annotate.JsonIgnore, as otherwise, it simply did nothing.

Solution 5

Another easy way to handle this is to use the argument allowSetters=truein the annotation. This will allow the password to be deserialized into your dto but it will not serialize it into a response body that uses contains object.

example:

@JsonIgnoreProperties(allowSetters = true, value = {"bar"})
class Pojo{
    String foo;
    String bar;
}

Both foo and bar are populated in the object, but only foo is written into a response body.

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