如何在 java 中替换 for each using streams

【问题标题】：How to replace the for each using streams in java如何在 java 中替换 for each using streams
【发布时间】：2022-12-12 13:24:23
【问题描述】：

Dates.forEach(date -> {
            executeQuery(date, loads);
            
private void executeQuery(LocalDate date, ArrayList<Load> loads){
        MapSqlParameterSource source = new MapSqlParameterSource();
            source.addValue("date", date.toString());
            Load load = namedJdbcTemplate.queryForObject(Constants.SQL_QUERY, source,
                    new BeanPropertyRowMapper<>(Load.class));
            loads.add(load);
}

如何将流概念用于上述代码

【问题讨论】：

标签： java spring foreach java-8 java-stream

【解决方案1】：

这样的事情应该工作

// change your method like so            
private Load executeQuery(LocalDate date){
    MapSqlParameterSource source = new MapSqlParameterSource();
    source.addValue("date", date.toString());
    return namedJdbcTemplate.queryForObject(Constants.SQL_QUERY, source,
        new BeanPropertyRowMapper<>(Load.class));
}

// load your dates from somewhere
List<LocalDate> dates = getYourDates(); 
// now use the streams API to collect the query results into a new list
List<Load> loads = dates.stream()
  .map(this::executeQuery)
  .collect(Collectors.toList());

或者

List<Load> loads = getYourDates().stream()
  .map(this::executeQuery)
  .collect(Collectors.toList());

【讨论】：