maximum number of expressions in a list

Oracle 數據庫執行SQL時報錯，提示 maximum number of expressions in a list （列表中的最大表達式數爲 1000），這個錯誤的意思是指參數個數超過了1000
解決辦法：

1. 新建工具類:

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.function.BiFunction;
import java.util.function.Function;

public class FuncUtils2 {


  public static <T,U> void adjustDoSize(Collection<T> collection,U otherParam,
      BiFunction<List<T>,U,?> function,Function after){
    int step = 991;
    List<T> allId = null;
    if (collection instanceof List) {
      allId = (List<T>)collection;
    }
    else {
      allId = new ArrayList<>(collection);
    }

    if (after != null) {
      function = function.andThen(after);
    }

    int szAll = allId.size();
    //當個數超過1000時，分批查詢；
    if (szAll>=1000) {
      int n = (allId.size()+step-1)/step;
      for (int i=0; i<n; ++i) {
        int startIndex = i*step;
        int endIndex = startIndex+step;
        if (endIndex>szAll) {
          endIndex = szAll;
        }
        List<T> subList = allId.subList(startIndex,endIndex);
        function.apply(subList,otherParam);
      }
    }
    else {
      function.apply(allId,otherParam);
    }
  }

  public static <T,U,R> List<R> doQueryWithIn(Collection<T> collection,U otherParam,
      BiFunction<List<T>,U,List<R>> function){
    List<R> retList = new ArrayList<>();
    Function f = (x)->{
      retList.addAll((List)x);
      return retList;
    };
    adjustDoSize(collection,otherParam,function,f);
    return retList;
  }

}

2. 調用方法:

 FuncUtils.doQueryWithIn(uniqueIds,null,
        (x,y)->questionExtRepository.findByUniqueIdIn(x));