public static void main(String[] args) {
		
    	System.out.println("---------------- ");
    	/**
    	 * Google Guava提供了Joiner類專門用來連接String。
    	 * 譬如說有個String數組，裏面有"a","b","c"，
    	 * 我們可以通過使用StringBuilder來創建String "a,b,c"。
    	 */
    	Joiner joiner = Joiner.on(";");
    	String str1 = joiner.join(new String[]{"a","b","c"});
    	System.out.println(" str1 : " + str1);
    	
    	
    	/**
    	 * 當然Joiner.join還提供了參數為Iterable的overload形式。也就是說你可以傳各種List和Set。
    	 * 如果被連接String裏面要過濾null，可以這樣
    	 */
    	Joiner joiner2 = Joiner.on(";").skipNulls(); //過濾null
    	String str2 = joiner2.join(new String[]{"a","b",null,"c"});
    	List<String> list = new ArrayList<String>();
    	list.add("1");
    	list.add("2");
    	list.add(null);
    	list.add("3");

    	String str21 = joiner2.join(list);
    	System.out.println(" str2 : " + str2);
    	System.out.println(" str21 : " + str21);
    	
    	/**
    	 * 如果對null進行替換操作
    	 */
    	Joiner joiner3 = Joiner.on(";").useForNull("!");
    	String str3 = joiner3.join(new String[]{"a","b",null,"c"});
    	System.out.println(" str3 : " + str3);
    	
    	/**
    	 * Joiner還提供了appendTo函數,對傳入的StringBuider作處理
    	 */
    	Joiner joiner4 = Joiner.on(";");
    	StringBuilder ab = new StringBuilder("start : ");
    	StringBuilder str4 = joiner4.appendTo(ab, new String[]{"a","b","c"});
    	System.out.println(" str4 : " + str4.toString());
    	
    	/**
    	 * MapJoiner類也利用了Joiner提供的Map的join功能
    	 */
    	Map<Integer, String> map = new HashMap<Integer, String>();
    	map.put(1, "a");
    	map.put(2, "b");
    	MapJoiner joiner5 = Joiner.on(";").withKeyValueSeparator("→");
    	String str5 = joiner5.join(map);
    	System.out.println(" str5 : " + str5);
    	
    	//url拼接
    	Map<String, Object> map2 = new HashMap<String, Object>();
    	map2.put("param1", "HAN");
    	map2.put("param2", 2);
    	MapJoiner joiner6 = Joiner.on("&").withKeyValueSeparator("=");
    	String str6 = joiner6.join(map2);
    	System.out.println(" str6 : " + str6);
    	
    	String str7 = joiner6.join(ImmutableMap.of("id","123","name","green"));
    	System.out.println(" str7 : " + str7);
    	
    	//分割
    	final Map<String, String> join = Splitter.on("&").withKeyValueSeparator("=").split("id=123&name=green&param1=HAN&param2=2");
    	System.out.println(" map :" + join.toString());
	}

本文出自 “我的JAVA世界” 博客，請務必保留此出處http://hanchaohan.blog.51cto.com/2996417/1931272

Joiner的簡單了解