给定一个字符串列表List<String> strList, 统计里面每一个字符串的出现次数。 如: {"aa", "aa", "b"} 输出: {"aa", 2}, {"b", 1} 补充完整下面的方法: public Map<String, Integer> calStringArray(List<String> strList) { }
package baseTest; import java.util.*; public class Test { public static Map<String,Integer> calStringArray(List<String> strList){ Map<String,Integer> reult=null; if(strList!=null){ reult=new HashMap<>(); for (String s : strList) { Integer count = reult.get(s); if(count==null){ count=1; }else{ count++; } reult.put(s,count); } } return reult; } public static void main(String[] args) { String[] strings = {"aa", "aa", "b"}; Map<String,Integer> map = Test.calStringArray(Arrays.asList(strings)); for (Map.Entry<String, Integer> entry:map.entrySet()){ System.out.println(entry.getKey()+":"+entry.getValue()+"\t"); } } }