我不写代码，我只是代码的搬运工。

1.首先引入maven

		<!-- 融云SDK -->
		<dependency>
			<groupId>cn.rongcloud.im</groupId>
			<artifactId>server-sdk-java</artifactId>
			<version>3.1.14</version>
		</dependency>

2.设置群组操作

public class GroupUtil {
	// 此处替换成您的appKey
	private static final String appKey = RY_App_Key;
	// 此处替换成您的appSecret
	private static final String appSecret = RY_App_Secret;
	private static final RongCloud rongCloud = RongCloud.getInstance(appKey, appSecret);
	private static final Group Group = rongCloud.group;

	/**
	 * 创建群组方法
	 */
	public static String groupCreate(String userId, String username, String groupId, String groupTitle) {

		GroupMember[] members = { new GroupMember().setId(userId) };
		GroupModel group = new GroupModel().setId(groupId).setMembers(members).setName(groupTitle);
		Result groupCreateResult;
		try {
			groupCreateResult = (Result) Group.create(group);
			System.out.println("group create result:  " + groupCreateResult.toString());
			RyMessage.sendMessage(groupId, username + "创建群组");
			return groupCreateResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 邀请用户加入群组
	 * 
	 * @param userId
	 * @param username
	 * @param groupId
	 * @param groupTitle
	 * @return
	 */
	public static String inviteMembersJoinGroup(String userId, String inviteUsername, String beInviteUsername,
			String groupId, String groupTitle) {
		GroupMember[] members = { new GroupMember().setId(userId) };
		GroupModel group = new GroupModel().setId(groupId).setMembers(members).setName(groupTitle);
		Result groupInviteResult;
		try {
			groupInviteResult = (Result) rongCloud.group.invite(group);
			System.out.println("invite:  " + groupInviteResult.toString());
			RyMessage.sendMessage(groupId, "\"" + inviteUsername + "\" 邀请 \"" + beInviteUsername + "\" 进入群组");
			return groupInviteResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 用户加入指定群组
	 */
	public static String joinGroup(String userId, String username, String groupId, String groupTitle) {
		GroupMember[] members = { new GroupMember().setId(userId) };
		GroupModel group = new GroupModel().setId(groupId).setMembers(members).setName(groupTitle);
		Result groupJoinResult;
		try {
			groupJoinResult = (Result) Group.join(group);
			RyMessage.sendMessage(groupId, username + "加入群组");
			System.out.println("join:  " + groupJoinResult.toString());
			return groupJoinResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 查询群成员方法
	 *
	 */
	public static String listGroupUser(String groupId) {
		GroupModel group = new GroupModel().setId(groupId);
		GroupUserQueryResult getMemberesult;
		try {
			getMemberesult = Group.get(group);
			System.out.println("group getMember:  " + getMemberesult.toString());
			return getMemberesult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 刷新群组信息方法
	 * 
	 * @param groupId
	 * @return
	 */
	public static String refreshGroup(String groupId, String groupName) {
		GroupModel group = new GroupModel().setId(groupId).setName(groupName);
		Result refreshResult;
		try {
			refreshResult = (Result) Group.update(group);
			System.out.println("refresh:  " + refreshResult.toString());
			return refreshResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * API 文档: http://www.rongcloud.cn/docs/server_sdk_api/group/group.html#quit
	 *
	 * 退出群组
	 *
	 */
	public static String quitGroupMembers(String userId, String username, String groupId, String groupName) {
		GroupMember[] members = { new GroupMember().setId(userId) };
		GroupModel group = new GroupModel().setId(groupId).setMembers(members).setName(groupName);
		Result groupQuitResult;
		try {
			groupQuitResult = (Result) Group.quit(group);
			RyMessage.sendMessage(groupId, username + " 退出群组");
			System.out.println("refresh:  " + groupQuitResult.toString());
			return groupQuitResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 解散群组
	 * 
	 * @param userId
	 * @param groupId
	 * @return
	 */
	public static String dismissGroup(String userId, String groupId) {
		GroupMember[] members = new GroupMember[] { new GroupMember().setId(userId) };
		GroupModel group = new GroupModel().setId(groupId).setMembers(members);
		Result groupDismissResult;
		try {
			groupDismissResult = (Result) Group.dismiss(group);
			System.out.println("refresh:  " + groupDismissResult.toString());
			return groupDismissResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 邀请用户加入群组
	 */

	public static String invitedJoinGroup(String userId, String username, String groupId, String groupName) {
		GroupMember[] members = new GroupMember[] { new GroupMember().setId(userId) };
		GroupModel group = new GroupModel().setId(groupId).setMembers(members).setName(groupName);
		Result groupInviteResult;
		try {
			groupInviteResult = (Result) rongCloud.group.invite(group);
			System.out.println("invite:  " + groupInviteResult.toString());
			RyMessage.sendMessage(groupId, username + "邀请用户加入群组");
			return groupInviteResult.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
	}
}