java - 使用Java 8，当且仅当它具有空值时，如何在List <Object []>中为obj [4]设置字符串常量？

我得到具有6列的resultSet。现在，我将其分配给对象数组列表。事实是列表中每个对象的Object [4]可以为null，也可以不为null。
如果它具有空值，则必须使用字符串常量“ System”进行设置。
如何使用Java 8做到这一点？请协助！

List<Object[]> loanEntries = loanDAO.getLoanMappingDetails(QueryConstants.LOAN_MAPPING);

最佳答案

我了解到loanEntries是您正在谈论的变量。

List<Object[]> loanEntries = new ArrayList<>();
        loanEntries.add(new Object[]{"a","b","c","d",null,"f"});
        loanEntries.add(new Object[]{"aa","bb","cc","dd",null,"ff"});

        loanEntries.stream()
                .filter(objects -> objects[4] == null)
                .forEach(objects -> objects[4] = "System");

        loanEntries.stream()
                .forEach(objects -> {
                    for (Object object : objects) {
                        System.out.println(object);
                    }
                });

输出

a
b
c
d
System
f
aa
bb
cc
dd
System
ff