JAVA8 StringJoiner，String.join和StringBuffer 拼接字符串

使用StringJoiner 拼接：

		List<ContactRoleAlternativeDetail> cr = new ArrayList<>();
		ContactRoleAlternativeDetail crd = new ContactRoleAlternativeDetail();
		crd.setContactRoleName("LEGAL");
		ContactRoleAlternativeDetail crd1 = new ContactRoleAlternativeDetail();
		crd1.setContactRoleName("MAIN");
		cr.add(crd);
		cr.add(crd1);
		
		StringJoiner roleJoiner = new StringJoiner(",");//需要的间隔符
		// Lambda 实现拼接
		cr.forEach(role -> roleJoiner.add(role.getContactRoleName()));
		
		System.out.println("Lambda实现拼接结果：" + roleJoiner.toString());
		
		StringJoiner roleJoiner1 = new StringJoiner(",");//需要的间隔符
		for (ContactRoleAlternativeDetail role : cr) {
			roleJoiner1.add(role.getContactRoleName());
		}
		
		System.out.println("使用for循环时间拼接结果：" + roleJoiner1);		List<ContactRoleAlternat