Simple Class to add Salesforce Chatter posts with links, urls and mentions.

ChatterUtils

public with sharing class ChatterUtils {
  
  // makes a simple chatter text post to the specified user from the running user 
  public static void simpleTextPost(Id userId, String postText) { 
    
    ConnectApi.FeedType feedType = ConnectApi.FeedType.UserProfile;
    
    ConnectApi.MessageBodyInput messageInput = new ConnectApi.MessageBodyInput();
    messageInput.messageSegments = new List<ConnectApi.MessageSegmentInput>();
    
    // add the text segment
    ConnectApi.TextSegmentInput textSegment = new ConnectApi.TextSegmentInput();
    textSegment.text = postText;
    messageInput.messageSegments.add(textSegment);
    
    ConnectApi.FeedItemInput feedItemInput = new ConnectApi.FeedItemInput();
    feedItemInput.body = messageInput;
    
    // post it
    ConnectApi.ChatterFeeds.postFeedItem(null, feedType, userId, feedItemInput, null);  

  }     
  
  // makes a chatter post with some text and a link
  public static void simpleLinkPost(Id userId, String postText, String url, String urlName) {    
    
    ConnectApi.FeedItemInput feedItemInput = new ConnectApi.FeedItemInput();
    feedItemInput.body = new ConnectApi.MessageBodyInput();
    
    // add the text segment
    ConnectApi.TextSegmentInput textSegment = new ConnectApi.TextSegmentInput();
    feedItemInput.body.messageSegments = new List<ConnectApi.MessageSegmentInput>();
    textSegment.text = postText;
    feedItemInput.body.messageSegments.add(textSegment);
    
    // add the attachment
    ConnectApi.LinkAttachmentInput linkIn = new ConnectApi.LinkAttachmentInput();
    linkIn.urlName = urlName;
    linkIn.url = url;
    feedItemInput.attachment = linkIn;
    
    // post it!
    ConnectApi.ChatterFeeds.postFeedItem(null, ConnectApi.FeedType.News, userId, feedItemInput, null);
    
  }   
  
  // makes a simple chatter text post to the specified user from the running user 
  public static void mentionTextPost(Id userId, Id userToMentionId, String postText) { 
    
    ConnectApi.MessageBodyInput messageInput = new ConnectApi.MessageBodyInput();
    messageInput.messageSegments = new List<ConnectApi.MessageSegmentInput>();
    
    // add some text before the mention
    ConnectApi.TextSegmentInput textSegment = new ConnectApi.TextSegmentInput();
    textSegment.text = 'Hey ';
    messageInput.messageSegments.add(textSegment);
    
    // add the mention
    ConnectApi.MentionSegmentInput mentionSegment = new ConnectApi.MentionSegmentInput();
    mentionSegment.id = userToMentionId;
    messageInput.messageSegments.add(mentionSegment);
    
    // add the text that was passed
    textSegment = new ConnectApi.TextSegmentInput();
    textSegment.text = postText;
    messageInput.messageSegments.add(textSegment);
    
    ConnectApi.FeedItemInput input = new ConnectApi.FeedItemInput();
    input.body = messageInput;
    
    // post it
    ConnectApi.ChatterFeeds.postFeedItem(null, ConnectApi.FeedType.UserProfile, userId, input, null);

  }     
  
  // pass the user's id or 'me' to get current running user's news 
  public static ConnectApi.FeedItemPage getNewsFeed(String userId) { 
    return ConnectApi.ChatterFeeds.getFeedItemsFromFeed(null, ConnectApi.FeedType.News, userId);
  }      

}