diff --git a/build.gradle b/build.gradle
index 3212546..3956fdb 100644
--- a/build.gradle
+++ b/build.gradle
@@ -22,6 +22,7 @@
     testImplementation('org.springframework.boot:spring-boot-starter-test') {
         exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
     }
+    compile("com.fasterxml.jackson.core:jackson-databind")
 }
 
 test {
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 9492014..e0b3fb8 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.0.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/src/main/java/com/example/springtest/demo/entities/User.java b/src/main/java/com/example/springtest/demo/entities/User.java
new file mode 100644
index 0000000..d298436
--- /dev/null
+++ b/src/main/java/com/example/springtest/demo/entities/User.java
@@ -0,0 +1,42 @@
+package com.example.springtest.demo.entities;
+
+public class User {
+    public String uId;
+    public String name;
+    public String password;
+    public String uri;
+
+    public User(String uId, String name, String password) {
+        this.uId = uId;
+        this.name = name;
+        this.password = password;
+    }
+
+    public String getuId() {
+        return uId;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setuId(String uId) {
+        this.uId = uId;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public void setUri(String uri) {
+        this.uri = uri;
+    }
+}
diff --git a/src/main/java/com/example/springtest/demo/resources/UserRest.java b/src/main/java/com/example/springtest/demo/resources/UserRest.java
new file mode 100644
index 0000000..aaa26eb
--- /dev/null
+++ b/src/main/java/com/example/springtest/demo/resources/UserRest.java
@@ -0,0 +1,82 @@
+package com.example.springtest.demo.resources;
+
+import com.example.springtest.demo.entities.User;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.lang.Nullable;
+import org.springframework.stereotype.Component;
+
+import javax.persistence.NoResultException;
+import javax.ws.rs.*;
+import javax.ws.rs.core.MediaType;
+import java.util.*;
+
+@Component
+@Path("/users")
+public class UserRest {
+
+    private Map<String, User> users = new HashMap<>();
+//    @GET
+//    public String getUser(@QueryParam("uId") String uId, @QueryParam("name") String name, @QueryParam("password") String password) {
+//        ObjectMapper objectMapper = new ObjectMapper();
+//        String json = null;
+//        try {
+//            json = objectMapper.writeValueAsString(new User(uId, name, password));
+//        } catch (JsonProcessingException e) {
+//            e.printStackTrace();
+//        }
+//        return json;
+//    }
+    @GET
+    @Produces(MediaType.APPLICATION_JSON) // 戻り値をJSONで返す.
+    public Collection<User> getUsers() {
+        return users.values();    // JSONが返る
+    }
+
+    @Path("/{uId}")
+    @GET
+    @Produces(MediaType.APPLICATION_JSON) // 戻り値をJSONで返す.
+    public User getUser(@PathParam("uId") String uId) {
+        User user = users.get(uId);
+        if (user != null) {
+            return user;    // JSONが返る
+        } else { // uIdが無ければ
+            throw new WebApplicationException(404);    // 404が返る
+        }
+    }
+
+    @POST
+    @Produces(MediaType.APPLICATION_JSON)
+    public User createUser(@FormParam("name") String name, @FormParam("password") String password) {
+        String uId = UUID.randomUUID().toString();
+        User user = new User(uId, name, password);
+        users.put(uId, user);
+        return user;
+    }
+
+    @Path("/{uId}")
+    @PUT
+    @Produces(MediaType.APPLICATION_JSON)
+    public User updateUser(@PathParam("uId") String uId, @Nullable @FormParam("name") String name, @Nullable @FormParam("password") String password) {
+        User user = users.get(uId);
+        if (user != null) {
+            user.setName(name);
+            user.setPassword(password);
+            return user;    // JSONが返る
+        } else { // uIdが無ければ
+            throw new WebApplicationException(404);    // 404が返る
+        }
+    }
+
+    @Path("/{uId}")
+    @DELETE
+    @Produces(MediaType.APPLICATION_JSON)
+    public User deleteUser(@PathParam("uId") String uId) {
+        User user = users.remove(uId);
+        if (user != null) {
+            return user;    // JSONが返る
+        } else { // uIdが無ければ
+            throw new WebApplicationException(410);    // 410が返る(GONE)
+        }
+    }
+}