package com.sakamichi46.model;

import com.fasterxml.jackson.annotation.JsonFormat;
import java.util.Date;
import lombok.Getter;
import lombok.Setter;

/**
 *
 * @author kikuta
 */
@Getter @Setter
public class Member {
    private String name;
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
    private Date birthday;
    private String bloodType;
    private String constellation;
    private String profilePhotoUri;
    private String blogUri;
}

package com.sakamichi46.model;

import java.util.Date;
import lombok.Getter;
import lombok.Setter;

/**
 *
 * @author kikuta
 */
@Getter @Setter
public class Member {
    private String name;
    private Date birthday;
    private String bloodType;
    private String constellation;
    private String profilePhotoUri;
    private String blogUri;
}

--- 
+++ 
@@ -1,5 +1,6 @@
 package com.sakamichi46.model;
 
+import com.fasterxml.jackson.annotation.JsonFormat;
 import java.util.Date;
 import lombok.Getter;
 import lombok.Setter;
@@ -11,6 +12,7 @@
 @Getter @Setter
 public class Member {
     private String name;
+    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
     private Date birthday;
     private String bloodType;
     private String constellation;
Modify date format of json