Lambda实现两个List根据某个字段比较增量、减量、同量方法_lamda两个数组比较根据某个字段取出不同的值-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_44347111/article/details/123559007

该代码示例展示了如何使用Java Stream处理两个客户信息列表，分别找出减量（在保-非在保）、增量（新增用户）和同量（更新用户）的数据。通过对oldInfoList和latestInfoList进行过滤操作，实现数据对比并打印结果。

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 public static void main(String[] args) {
        List<TestBody> oldInfoList = new ArrayList<>();
        TestBody customer1 = new TestBody();
        customer1.setId("old1");
        customer1.setCustomerId("new111111");
        oldInfoList.add(customer1);

        TestBody customer2 = new TestBody();
        customer2.setId("old2");
        customer2.setCustomerId("new222222");
        oldInfoList.add(customer2);

        TestBody customer3 = new TestBody();
        customer3.setId("old3");
        customer3.setCustomerId("old888888");
        oldInfoList.add(customer3);

        TestBody customer4 = new TestBody();
        customer4.setId("old4");
        customer4.setCustomerId("old999999");
        oldInfoList.add(customer4);


        List<TestBody> latestInfoList = new ArrayList<>();
        TestBody customerInfoDO1 = new TestBody();
        customerInfoDO1.setId("new1");
        customerInfoDO1.setCustomerId("new111111");
        latestInfoList.add(customerInfoDO1);

        TestBody customerInfoDO2 = new TestBody();
        customerInfoDO2.setId("new2");
        customerInfoDO2.setCustomerId("new222222");
        latestInfoList.add(customerInfoDO2);

        TestBody customerInfoDO3 = new TestBody();
        customerInfoDO3.setId("new3");
        customerInfoDO3.setCustomerId("new333333");
        latestInfoList.add(customerInfoDO3);

        TestBody customerInfoDO4 = new TestBody();
        customerInfoDO4.setId("new4");
        customerInfoDO4.setCustomerId("new444444");
        latestInfoList.add(customerInfoDO4);


        System.out.println("老数据："+ oldInfoList);
        System.out.println("新数据："+ latestInfoList);

        // 4.1、减量：oldSyncSmsInfoList(customerType：在保->非在保（["type1"]->["type5"]）)
        List<TestBody> reduceList = oldInfoList.stream().filter(x -> !latestInfoList.stream().map(TestBody::getCustomerId).collect(Collectors.toList())
                .contains(x.getCustomerId())).collect(Collectors.toList());
        if (!ObjectUtils.isEmpty(reduceList)) {
            log.info("减量用户" + reduceList);
        }

        // 4.2、增量：(新增用户)
        List<TestBody> addList = latestInfoList.stream().filter(x -> !oldInfoList.stream().map(TestBody::getCustomerId)
                .collect(Collectors.toList()).contains(x.getCustomerId())).collect(Collectors.toList());
        if (!ObjectUtils.isEmpty(addList)) {
            log.info("新增用户:" + addList);
        }

        // 4.3、同量：更新用户数据,抓取最新的更新
        List<TestBody> sameList = latestInfoList.stream().filter(x -> oldInfoList.stream().map(TestBody::getCustomerId).collect(Collectors.toList())
                .contains(x.getCustomerId())).collect(Collectors.toList());
        if (!ObjectUtils.isEmpty(sameList)) {
            log.info("同量用户信息:" + sameList);
        }

    }

实现效果如下：