集合

1. list到map

   Map<String, Company> objMap = list.stream().collect(Collectors.toMap(Company::getCode, (obj) -> obj));
   

2. 循环处理(java8) ```java // 方法1 List userList = Lists.newArrayList(); originList.forEach((party)->userList.add(new User(party)));

// 方法2，同时可以支持filter(过滤出需要返回的) List userNameList = originList.stream().map(obj -> { return obj.getName(); }).collect(Collectors.toList());

Map也可以同样循环处理

## list
1. 字符串[]到list
```java
List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");
Arrays.asList(new String[] {"Larry", "Moe", "Curly"})

1. list到字符串

   Joiner.on(",").join(list);
   

2. 字符串到list

   Splitter. on("," ).omitEmptyStrings().splitToList("sd,dsf");
   

3. 比较

   Collections.sort(listA, new Comparator<Class4Sort>() {
      public int compare(Class4Sort s1, Class4Sort s2) {
          // 升序排的话就是第一个参数.compareTo(第二个参数), 降序排的话就是第二个参数.compareTo(第一个参数)
          return s2.getNumber().compareTo(s1.getNumber());
      }
   }
   

map

1. map到字符串

   Map<String, String> map = this.getRequestParams(request);
   String body = Joiner.on("&").withKeyValueSeparator("=").join(map);
   

2. 字符串到map

   final Map<String, String> join =Splitter.on("&").withKeyValueSeparator("=").split("id=123&name=green");
   

3. map循环

   for (Map.Entry<String, String> entry : params.entrySet()) {
        String.format("%s=[%s]", entry.getKey(),entry.getValue());
   }
   允许删除
   // Map<String, Integer>
   Iterator it = map.keySet().iterator();
   while (it.hasNext()) {
    String key = (String) it.next();
    Integer val = map.get(key);
    if (val < 100) {
        it.remove();
    }
   }
   

4. 初始化map

   ImmutableMap.<String, String>builder().put("uri", uri).put("body", body).build();
   ####从一个list生成另外一个list（Advertise转换成ClientBanner）
   Lists.transform(listAdv, new Function<Src, Target>() {
    @Override
    public Target apply(Src src) {
         return new Target(src);
    }
   });