List转换为字符串并添加分隔符

// 方法一：
public String listToString(List list, char separator) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < list.size(); i++) {
        sb.append(list.get(i)).append(separator);
    }
    return list.isEmpty()?"":sb.toString().substring(0, sb.toString().length() - 1);
}

// 方法二：
public String listToString2(List list, char separator) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < list.size(); i++) {
        if (i == list.size() - 1) {
            sb.append(list.get(i));
        } else {
            sb.append(list.get(i));
            sb.append(separator);
        }
    }
    return sb.toString();
}

// 方法三：
public String listToString3(List list, char separator) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < list.size(); i++) {
        sb.append(list.get(i));
        if (i < list.size() - 1) {
            sb.append(separator);
        }
    }
    return sb.toString();
}

// 方法四：
public class Separator {
    private String next = "";
    private String separator;

    public Separator(String separator) {
        this.separator = separator;
    }

    public String get() {
        String result = next;
        next = separator;
        return result;
    }
}

public String listToString4(List<String> list, Separator separator) {
    StringBuilder sb = new StringBuilder();
    for (String s : list) {
        if (s != null && !"".equals(s)) {
            sb.append(separator.get()).append(s);
        }
    }
    return sb.toString();
}

// 方法五：
public String listToString5(List list, char separator) {
    return org.apache.commons.lang.StringUtils.join(list.toArray(),separator);
}