java8特性 .stream()的使用

作者: 海内灬存知己 | 来源:发表于2023-01-11 15:16 被阅读0次

java中List去重
Stream流
java 8 stream 流详细教程
Java8 Stream 流的重用
转发微博 Qzone 微信 java8：stream特性详解，
Java8新特性
使用Collectors.toMap报java.lang.Ill
Java8特性③Stream的使用
Java8新特性系列（流性能）
Stream API

1：java8特性 .stream()的使用

public void updateMySceneEngineBeanList() {
        Long userId = DataMMKV.getUserId();
        List<SceneEngineBean> sceneEngineBeans = SceneEngineDepository
                .getInstance()
                .getSceneEngineListData(userId);

        List<SceneEngineBean> localSceneEngineBeans = SceneEngineDepository
                .getInstance()
                .getLocalSceneEngineStateListData(userId)
                .stream()
                .map(LocalSceneEngineBean::getSceneEngineBean)
                .collect(Collectors.toList());

        sceneEngineBeans.addAll(localSceneEngineBeans);

        List<ItemBean<SceneEngineBean>> beans = sceneEngineBeans
                .stream()
                .map(sceneEngineBean -> {
                    ItemBean<SceneEngineBean> itemBean = new ItemBean<>();
                    itemBean.setCode(String.valueOf(sceneEngineBean.getId()));
                    itemBean.setName(sceneEngineBean.getName());
                    itemBean.setState(SimpleSceneEngineExecuteService.getInstance().isOpen(sceneEngineBean.getId()));
                    itemBean.setData(sceneEngineBean);
                    Log.d(TAG, "map: size: " + GsonUtils.toJson(sceneEngineBean));
                    return itemBean;
                }).collect(Collectors.toList());
    }

 public SceneEngineBean getSceneEngineBean(){
        SceneEngineBean sceneEngineBean = new SceneEngineBean();
        sceneEngineBean.setId(this.getId());
        sceneEngineBean.setName(this.getName());
        sceneEngineBean.setRuleJson(this.getRuleJson());
        sceneEngineBean.setType(this.getType());
        sceneEngineBean.setUserId(this.getUserId());
        sceneEngineBean.setSceneEngineRule(this.getSceneEngineRule());
        sceneEngineBean.setKeyType(KEY_TYPE_LOCAL);
        sceneEngineBean.setKeyValue(this.getKeyId());
        return sceneEngineBean;
    }

.stream()的意思是把List转化成为流
.map的意思是转化
LocalSceneEngineBean::getSceneEngineBean的意思是通过LocalSceneEngineBean里的getSceneEngineBean方法，把LocalSceneEngineBean转化成SceneEngineBean。
当然了用下面的x->{}也可以实现