java集合工具类 浅谈常用字符串与集合类转换的工具类

import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.TreeSet;

public class MyStringUtils {

  /**
   * 将字符串转换成set集合类
   * 分隔符是任意空白字符
   */
  public static Set<String> parseParameterList(String values) {
    Set<String> result = new TreeSet<String>();
    if (values != null && values.trim().length() > 0) {
      // the spec says the scope is separated by spaces
      String[] tokens = values.split("[\\s+]");//匹配任意空白字符
      result.addAll(Arrays.asList(tokens));
    }
    return result;
  }

  /**
   * 把集合转化成指定形式的字符串
   */
  public static String formatParameterList(Collection<String> value) {
    return value == null ? null : StringUtils.collectionToDelimitedString(value, ",");//指定分隔符
  }

  /**
   * 从query的字符串中抽取需要的键值对存入map中
   * query的形式name=god&password=111&method=up
   */
  public static Map<String, String> extractMap(String query) {
    Map<String, String> map = new HashMap<String, String>();
    Properties properties = StringUtils.splitArrayElementsIntoProperties(
        StringUtils.delimitedListToStringArray(query, "&"), "=");
    if (properties != null) {
      for (Object key : properties.keySet()) {
        map.put(key.toString(), properties.get(key).toString());
      }
    }
    return map;
  }

  /**
   * 比较两个集合是否相等
   */
  public static boolean containsAll(Set<String> target, Set<String> members) {
    target = new HashSet<String>(target);
    target.retainAll(members);//取两个集合的交集
    return target.size() == members.size();
  }
}