请参阅以下代码。哈希映射HstTime和HstName中的键“H_0000001”和“H_0000002”被其他唯一键覆盖。“H_000002”被“H_00000010”覆盖，“H_0000001”被“H_00000012”覆盖。
package JavaTutes;
import java.util.*;
public class TCProcessData
{
String Unit1HST1ID = "H_0000001";
String Unit1HST2ID = "H_0000002";
String Unit1HST3ID = "H_0000003";
String Unit1HST4ID = "H_0000004";
String Unit2HST1ID = "H_0000005";
String Unit2HST2ID = "H_0000006";
String Unit3HST1ID = "H_0000007";
String Unit3HST2ID = "H_0000008";
String Unit3HST3ID = "H_0000009";
String Unit3HST4ID = "H_00000010";
String Unit3HST5ID = "H_00000011";
String Unit3HST6ID = "H_00000012";
String Unit4HST1ID = "H_00000013";
String Unit4HST2ID = "H_00000014";
String Unit4HST3ID = "H_00000015";
String Unit4HST4ID = "H_00000016";
String Unit5HST1ID = "H_00000017";
String Unit5HST2ID = "H_00000018";
String Unit5HST3ID = "H_00000019";
String Unit5HST4ID = "H_00000020";
String Unit5HST5ID = "H_00000021";
String Unit5HST6ID = "H_00000022";
String Unit5HST7ID = "H_00000023";
String Unit5HST8ID = "H_00000024";
String Unit5HST9ID = "H_00000025";
String Unit6HST1ID = "H_00000026";
String Unit6HST2ID = "H_00000027";
String Unit6HST3ID = "H_00000028";
String Unit6HST4ID = "H_00000029";
String Unit1HST1Name = "Some Name 1";
String Unit1HST2Name = "Some Name 2";
String Unit1HST3Name = "Some Name 3";
String Unit1HST4Name = "Some Name 4";
String Unit2HST1Name = "Some Name 5";
String Unit2HST2Name = "Some Name 6";
String Unit3HST1Name = "Some Name 7";
String Unit3HST2Name = "Some Name 8";
String Unit3HST3Name = "Some Name 9";
String Unit3HST4Name = "Some Name 10";
String Unit3HST5Name = "Some Name 11";
String Unit3HST6Name = "Some Name 12";
String Unit4HST1Name = "Some Name 13";
String Unit4HST2Name = "Some Name 14";
String Unit4HST3Name = "Some Name 15";
String Unit4HST4Name = "Some Name 16";
String Unit5HST1Name = "Some Name 17";
String Unit5HST2Name = "Some Name 18";
String Unit5HST3Name = "Some Name 19";
String Unit5HST4Name = "Some Name 20";
String Unit5HST5Name = "Some Name 21";
String Unit5HST6Name = "Some Name 22";
String Unit5HST7Name = "Some Name 23";
String Unit5HST8Name = "Some Name 24";
String Unit5HST9Name = "Some Name 25";
String Unit6HST1Name = "Some Name 26";
String Unit6HST2Name = "Some Name 27";
String Unit6HST3Name = "Some Name 28";
String Unit6HST4Name = "Some Name 29";
String Unit1HST1Time = "4.57";
String Unit1HST2Time = "2.34";
String Unit1HST3Time = "1.56";
String Unit1HST4Time = "4.23";
String Unit2HST1Time = "2.78";
String Unit2HST2Time = "4.21";
String Unit3HST1Time = "4.34";
String Unit3HST2Time = "3.45";
String Unit3HST3Time = "2.56";
String Unit3HST4Time = "6.67";
String Unit3HST5Time = "7.78";
String Unit3HST6Time = "5.89";
String Unit4HST1Time = "2.12";
String Unit4HST2Time = "1.23";
String Unit4HST3Time = "3.34";
String Unit4HST4Time = "4.45";
String Unit5HST1Time = "4.56";
String Unit5HST2Time = "5.67";
String Unit5HST3Time = "3.78";
String Unit5HST4Time = "3.89";
String Unit5HST5Time = "2.89";
String Unit5HST6Time = "2.78";
String Unit5HST7Time = "6.12";
String Unit5HST8Time = "7.23";
String Unit5HST9Time = "3.56";
String Unit6HST1Time = "4.67";
String Unit6HST2Time = "3.78";
String Unit6HST3Time = "3.78";
String Unit6HST4Time = "4.12";
String Unit1ID = "U_000001";
String Unit2ID = "U_000002";
String Unit3ID = "U_000003";
String Unit4ID = "U_000004";
String Unit5ID = "U_000005";
String Unit6ID = "U_000006";
String Unit1Name = "Some Unit1";
String Unit2Name = "Some Unit2";
String Unit3Name = "Some Unit3";
String Unit4Name = "Some Unit4";
String Unit5Name = "Some Unit5";
String Unit6Name = "Some Unit6";
String[] unitItemID = {Unit1ID, Unit2ID, Unit3ID,
Unit4ID, Unit5ID, Unit6ID};
String[] unitItemName = {Unit1Name, Unit2Name,
Unit3Name, Unit4Name, Unit5Name, Unit6Name};
private String[] listOfUnits = null;
private String[] hstIDs = null;
private Double[] hstTimes = null;
private Double unitTime = 0.00;
String unitID = null;
private double hstTime = 0.00;
//hashmap key - hstID. value is unit id
private static HashMap<String, String[]> UnitChildren = new HashMap<String, String[]>();
//hashmap key - hst id,value is hst time
private HashMap<String, Double> HstTime = new HashMap<String, Double>();
//hashmap key - hst id,value is hst name
private HashMap<String, String> HstName = new HashMap<String, String>();
public TCProcessData()
{
String[] unit1HSTID = {this.Unit1HST1ID, this.Unit1HST2ID,
this.Unit1HST3ID, this.Unit1HST4ID};
String[] unit2HSTID = {this.Unit2HST1ID, this.Unit2HST2ID};
String[] unit3HSTID = {this.Unit3HST1ID, this.Unit3HST2ID,
this.Unit3HST3ID, this.Unit3HST4ID, this.Unit3HST5ID, this.Unit3HST6ID};
String[] unit4HSTID = {this.Unit4HST1ID, this.Unit4HST2ID,
this.Unit4HST3ID, this.Unit4HST4ID};
String[] unit5HSTID = {this.Unit5HST1ID, this.Unit5HST2ID,
this.Unit5HST3ID, this.Unit5HST4ID, this.Unit5HST5ID, this.Unit5HST6ID,
this.Unit5HST7ID, this.Unit5HST8ID, this.Unit5HST9ID};
String[] unit6HSTID = {this.Unit6HST1ID, this.Unit6HST2ID,
this.Unit6HST3ID, this.Unit6HST4ID};
String[] unit1HSTName = {this.Unit1HST1Name, this.Unit1HST2Name,
this.Unit1HST3Name, this.Unit1HST4Name};
String[] unit2HSTName = {this.Unit2HST1Name, this.Unit2HST2Name};
String[] unit3HSTName = {this.Unit3HST1Name, this.Unit3HST2Name,
this.Unit3HST3Name, this.Unit3HST4Name, this.Unit3HST5Name, this.Unit3HST6Name};
String[] unit4HSTName = {this.Unit4HST1Name, this.Unit4HST2Name,
this.Unit4HST3Name, this.Unit4HST4Name};
String[] unit5HSTName = {this.Unit5HST1Name, this.Unit5HST2Name,
this.Unit5HST3Name, this.Unit5HST4Name, this.Unit5HST5Name, this.Unit5HST6Name,
this.Unit5HST7Name, this.Unit5HST8Name, this.Unit5HST9Name};
String[] unit6HSTName = {this.Unit6HST1Name, this.Unit6HST2Name,
this.Unit6HST3Name, this.Unit6HST4Name};
String[] unit1HSTTime = {this.Unit1HST1Time, this.Unit1HST2Time,
this.Unit1HST3Time, this.Unit1HST4Time};
String[] unit2HSTTime = {this.Unit2HST1Time, this.Unit2HST2Time};
String[] unit3HSTTime = {this.Unit3HST1Time, this.Unit3HST2Time,
this.Unit3HST3Time, this.Unit3HST4Time, this.Unit3HST5Time, this.Unit3HST6Time};
String[] unit4HSTTime = {this.Unit4HST1Time, this.Unit4HST2Time,
this.Unit4HST3Time, this.Unit4HST4Time};
String[] unit5HSTTime = {this.Unit5HST1Time, this.Unit5HST2Time,
this.Unit5HST3Time, this.Unit5HST4Time, this.Unit5HST5Time, this.Unit5HST6Time,
this.Unit5HST7Time, this.Unit5HST8Time, this.Unit5HST9Time};
String[] unit6HSTTime = {this.Unit6HST1Time, this.Unit6HST2Time,
this.Unit6HST3Time, this.Unit6HST4Time};
UnitChildren.put(this.Unit1ID, unit1HSTID);
for (int i = 0; i<unit1HSTID.length; i++)
{
hstTime = Double.valueOf(unit1HSTTime[i]);
HstTime.put(unit1HSTID[i], hstTime);
HstName.put(unit1HSTID[i], unit1HSTName[i]);
}
UnitChildren.put( Unit2ID, unit2HSTID );
for (int i = 0; i<unit2HSTID.length; i++)
{
hstTime = Double.valueOf(unit2HSTTime[i]);
HstTime.put(unit2HSTID[i], hstTime);
HstName.put(unit2HSTID[i], unit2HSTName[i]);
}
UnitChildren.put(Unit3ID, unit3HSTID);
for (int i = 0; i<unit3HSTID.length; i++)
{
hstTime = Double.valueOf(unit3HSTTime[i]);
HstTime.put(unit3HSTID[i], hstTime);
HstName.put(unit3HSTID[i], unit3HSTName[i]);
}
UnitChildren.put( Unit4ID, unit4HSTID);
for (int i = 0; i<unit4HSTID.length; i++)
{
hstTime = Double.valueOf(unit4HSTTime[i]);
HstTime.put(unit4HSTID[i], hstTime);
HstName.put(unit4HSTID[i], unit4HSTName[i]);
}
UnitChildren.put(Unit5ID, unit5HSTID);
for (int i = 0; i<unit5HSTID.length; i++)
{
hstTime = Double.valueOf(unit5HSTTime[i]);
HstTime.put(unit5HSTID[i], hstTime);
HstName.put(unit5HSTID[i], unit5HSTName[i]);
}
UnitChildren.put(Unit6ID, unit6HSTID);
for (int i = 0; i<unit6HSTID.length; i++)
{
hstTime = Double.valueOf(unit6HSTTime[i]);
HstTime.put(unit6HSTID[i], hstTime);
HstName.put(unit6HSTID[i], unit6HSTName[i]);
}
}
public int getNoOfRows()
{
return unitItemID.length;
}
public String[] getUnitIDs()
{
return unitItemID;
}
public String getUnitID(int row)
{
return unitItemID[row];
}
public String[] getUnitTitles()
{
return listOfUnits;
}
public HashMap<String, String[]> getUnitChildren()
{
return UnitChildren;
}
public HashMap<String, Double> getHstTime()
{
return HstTime;
}
public HashMap<String, String> getHstName()
{
return HstName;
}
public Double getUnitTime(int row)
{
this.unitID = this.getUnitID(row);
hstIDs = this.getUnitChildren().get(unitID);
for (int i=0; i<hstIDs.length; i++)
{
hstTimes[i] = this.getHstTime().get(hstIDs[i]);
unitTime = unitTime + hstTimes[i];
}
return unitTime;
}
public static void main(String[] args)
{
TCProcessData someData = new TCProcessData();
int rows = someData.getNoOfRows();
double unit1time = someData.getUnitTime(0);
double unit3time = someData.getUnitTime(2);
System.out.println(rows);
System.out.println(unit1time);
System.out.println(unit3time);
}
}
答案 0 :(得分：1)
被覆盖的是什么意思？由于Java计算哈希码的方式，您提到的String对将以相同的哈希值结束，但HashMap将优雅地处理这些冲突（通过使每个桶成为链接的条目列表，有效）。 / p>
答案 1 :(得分：0)
当我运行此代码时，我得到一个NullPointerException因为您试图将数据插入hstTimes方法中的getUnitTime数组中，但您从未实例化该数组。
另外HstTime包含29个密钥，这些密钥与所有unitnHSTID数组的成员数一致，所以我不确定您看到的是什么问题。