我的目标是从.csv文件中提取数据，并创建一个带有交互式菜单的数组以查找某些信息。我已经在这段代码上工作了几天。我遇到的唯一问题是此错误说明：“ CrimeDataClass无法转换为CrimeDataArray”。我已经看了2-3天了。我觉得这很简单。预先感谢您的帮助。
测试程序
package crimedata;
import java.time.Duration;
import java.time.Instant;
import java.util.Scanner;
public class TestCrimeData {
public static void main(String[] args) {
// Start time
Instant start = Instant.now();
String fileName = ("");
// Command Line Argument
try {
if (args.length == 1) {
fileName = args[0];
} // End If
else {
System.out.println("Require Crime.csv");
} // End Else
} // End Try
catch (Exception e) {
System.out.println("Try Again");
} // End Catch
// Create Data array
CrimeDataClass myCrimes = new CrimeDataClass();
这是我得到错误的地方。
// Interaction menu
menu(myCrimes);
其余代码没有错误。
// End time
Instant end = Instant.now();
System.out.println("Elapsed time (seconds): "
+ Duration.between(start, end).toNanos() / 1_000_000_000.0);
} // End Main
private static void menu(CrimeDataArray crimes) {
// Interaction with data
Scanner scannerIn = new Scanner(System.in);
System.out.println("********** Welcome to the US Crime Statistical Application **************************");
while (true) {
System.out.println("");
System.out.println("\nEnter the number of the question you want answered. Enter ‘Q’ to quit the program.\n"
+ "\n1. What were the percentages in population growth for each consecutive year from 1994 – 2013?"
+ "\n2. What year had the highest Violent crime rate?"
+ "\n3. What year had the lowest Violent crime rate?"
+ "\n4. What year had the highest Murder rate?"
+ "\n5. What year had the lowest Murder rate?"
+ "\n6. What year had the highest Robbery rate?"
+ "\n7. What year had the lowest Robbery rate?"
+ "\n8. What year had the highest Rape rate?"
+ "\n9. What year had the lowest Rape rate?"
+ "\n10. What year had the highest Aggravated Assault rate?"
+ "\n11. What year had the lowest Aggravated Assault rate?"
+ "\n12. What year had the highest Property crime rate?"
+ "\n13. What year had the lowest Property crime rate?"
+ "\n14. What year had the highest Burglary rate?"
+ "\n15. What year had the lowest Burglary rate?"
+ "\n16. What year had the highest Larceny theft rate?"
+ "\n17. What year had the lowest Larceny theft rate?"
+ "\n18. What year had the highest Motor Vehicle theft rate?"
+ "\n19. What year had the lowest Motor Vehicle theft rate?"
+ "\n20. What are the total crimes commited for each year from 1994 – 2013?"
+ "\nQ. Quit program."
+ "\nEnter your selection:");
// Read next line
String selection = scannerIn.nextLine().trim().toUpperCase();
if (selection.equals("Q")) {
System.out.println("Thank you for trying the US Crimes Statistics Program.");
// End loop when Q is entered
break;
} // End If
else {
switch (selection) {
case "1":
crimes.getPopulationGrowth();
break;
case "2":
System.out.printf("The Violent Crime rate was highest in %d", crimes.getMaxViolentCrimeRate());
break;
case "3":
System.out.printf("The Violent Crime rate was lowest in %d", crimes.getMinViolentCrimeRate());
break;
case "4":
System.out.printf("The Murder rate was highest in %d", crimes.getMaxMurderRate());
break;
case "5":
System.out.printf("The Murder rate was lowest in %d", crimes.getMinMurderRate());
break;
case "6":
System.out.printf("The Rape rate was highest in %d", crimes.getMaxRapeRate());
break;
case "7":
System.out.printf("The Rape rate was lowest in %d", crimes.getMinRapeRate());
break;
case "8":
System.out.printf("The Robbery rate was highest in %d", crimes.getMaxRobberyRate());
break;
case "9":
System.out.printf("The Robbery rate was lowest in %d", crimes.getMinRobberyRate());
break;
case "10":
System.out.printf("The Aggravated Assault rate was highest in %d", crimes.getMaxAggravatedAssaultRate());
break;
case "11":
System.out.printf("The Aggravated Assault rate was lowest in %d", crimes.getMinAggravatedAssaultRate());
break;
case "12":
System.out.printf("The Aggravated Assault rate was highest in %d", crimes.getMaxPropertyCrimeRate());
break;
case "13":
System.out.printf("The Aggravated Assault rate was lowest in %d", crimes.getMinPropertyCrimeRate());
break;
case "14":
System.out.printf("The Burglary rate was highest in %d", crimes.getMaxBurglaryRate());
break;
case "15":
System.out.printf("The Burglary rate was lowest in %d", crimes.getMinBurglaryRate());
break;
case "16":
System.out.printf("The Larceny theft was rate was highest in %d", crimes.getMaxLarcenyTheftRate());
break;
case "17":
System.out.printf("The Larceny theft was lowest in %d", crimes.getMinLarcenyTheftRate());
break;
case "18":
System.out.printf("The Motor Vehicle theft was rate was highest in %d", crimes.getMaxMotorVehicleTheftRate());
break;
case "19":
System.out.printf("The Motor Vehicle theft was lowest in %d", crimes.getMinMotorVehicleTheftRate());
case "20":
System.out.println(crimes.toString());
break;
default:
System.out.println("Invalid selection. Please try again.");
break;
} // End Switch
} // End Else
} // End While
scannerIn.close();
} // End Menu
} // End Class
班级：
public class CrimeDataClass {
// Variable for the class
private int year = 1994;
private int population = 0;
private int violentCrime = 0;
private double violentCrimeRate = 0.0;
private int murder = 0;
private double murderRate = 0.0;
private int rape = 0;
private double rapeRate = 0.0;
private int robbery = 0;
private double robberyRate = 0.0;
private int aggravatedAssault = 0;
private double aggravatedAssaultRate = 0.0;
private int propertyCrime = 0;
private double propertyCrimeRate = 0.0;
private int burglary = 0;
private double burglaryRate = 0.0;
private int larcenyTheft = 0;
private double larcenyTheftRate = 0.0;
private int motorVehicleTheft = 0;
private double motorVehicleTheftRate = 0.0;
// Default constructor
public CrimeDataClass() {
} // End Constructor
// Full Parameterize Constructor
public CrimeDataClass(int year, int population, int violentCrime, double violentCrimeRate,
int murder, double murderRate, int rape, double rapeRate, int robbery, double robberyRate,
int aggravatedAssault, double aggravatedAssaultRate, int propertyCrime, double propertyCrimeRate,
int burglary, double burglaryRate, int larcenyTheft, double larcenyTheftRate, int motorVehicleTheft,
double motorVehicleTheftRate) {
this.year = year;
this.population = population;
this.violentCrime = violentCrime;
this.violentCrimeRate = violentCrimeRate;
this.murder = murder;
this.murderRate = murderRate;
this.rape = rape;
this.rapeRate = rapeRate;
this.robbery = robbery;
this.robberyRate = robberyRate;
this.aggravatedAssault = aggravatedAssault;
this.aggravatedAssaultRate = aggravatedAssaultRate;
this.propertyCrime = propertyCrime;
this.propertyCrimeRate = propertyCrimeRate;
this.burglary = burglary;
this.burglaryRate = burglaryRate;
this.larcenyTheft = larcenyTheft;
this.larcenyTheftRate = larcenyTheftRate;
this.motorVehicleTheft = motorVehicleTheft;
this.motorVehicleTheftRate = motorVehicleTheftRate;
} // End Constructor
// Getter Method
public int getYear() {
return this.year;
}
public int getPopulation() {
return this.population;
}
public int getViolentCrime() {
return this.violentCrime;
}
public double getViolentCrimeRate() {
return this.violentCrimeRate;
}
public int getMurder() {
return this.murder;
}
public double getMurderRate() {
return this.murderRate;
}
public int getRape() {
return this.rape;
}
public double getRapeRate() {
return this.rapeRate;
}
public int getRobbery() {
return this.robbery;
}
public double getRobberyRate() {
return this.robberyRate;
}
public int getAggravatedAssault() {
return this.aggravatedAssault;
}
public double getAggravatedAssaultRate() {
return this.aggravatedAssaultRate;
}
public int getPropertyCrime() {
return this.propertyCrime;
}
public double getPropertyCrimeRate() {
return this.propertyCrimeRate;
}
public int getBurglary() {
return this.burglary;
}
public double getBurglaryRate() {
return this.burglaryRate;
}
public int getLarcenyTheft() {
return this.larcenyTheft;
}
public double getLarcenyTheftRate() {
return this.larcenyTheftRate;
}
public int getMotorVehicleTheft() {
return this.motorVehicleTheft;
}
public double getMotorVehicleTheftRate() {
return this.motorVehicleTheftRate;
} // End Getter Method
// Setter Method
// Objects are unchangeable due to using values from CSV
//toString Method
public String toString() {
return String.format("\nYear: %d"
+ "\nPopulation: %d"
+ "\nViolent Crime: %d"
+ "\nViolent Crime Rate: %.2f"
+ "\nMurder: %d"
+ "\nMurder Rate: %.2f"
+ "\nRape: %d"
+ "\nRape Rate: %.2f"
+ "\nRobbery: %d"
+ "\nRobbery Rate: %.2f"
+ "\nAggravated Assault: %d"
+ "\nAggravated Assault Rate: %.2f"
+ "\nProperty Crime: %d"
+ "\nProperty Crime Rate: %.2f"
+ "\nBurglary: %d"
+ "\nBurglary Rate: %.2f"
+ "\nLarceny-Theft: %d"
+ "\nLarceny-Theft Rate: %.2f"
+ "\nMotor Vehicle Theft: %d"
+ "\nMotor Vehicle Theft Rate: %.2f", this.year,
this.population, this.violentCrime, this.violentCrimeRate,
this.murder, this.murderRate, this.rape, this.rapeRate,
this.robbery, this.robberyRate, this.aggravatedAssault,
this.aggravatedAssaultRate, this.propertyCrime, this.propertyCrimeRate,
this.burglary, this.burglaryRate, this.larcenyTheft, this.larcenyTheftRate,
this.motorVehicleTheft, this.motorVehicleTheftRate);
} // End toString Method
} // End Class
数组：
package crimedata;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Scanner;
public class CrimeDataArray {
private CrimeDataClass[] crimes;
// csv file read setup
static Scanner scannerIn = null;
static FileInputStream in = null;
static BufferedReader inputStream = null;
static String fileLocation = "Crimes.csv";
// Method for reading Crime.csv file
public static void readFile() throws IOException {
int fileChar;
String fileLine;
in = new FileInputStream("Crime.csv");
System.out.println("ReadIt File Contents");
// Reads one char at a time
while ((fileChar = in.read()) != -1) {
// convert int to char
System.out.print((char) fileChar);
}
// Separate the file output
System.out.println("");
System.out.println("Crime.csv File Contents using BufferedReader");
// Use of Scanner and BufferedReader
inputStream = new BufferedReader(new FileReader("Crime.csv"));
scannerIn = new Scanner(inputStream);
while (scannerIn.hasNext()) {
if (scannerIn.hasNextInt()) {
System.out.println(scannerIn.nextInt());
}
if (scannerIn.hasNextDouble()) {
System.out.println(scannerIn.nextDouble());
} else {
scannerIn.next();
}
}
// Separe the file output
System.out.println("");
// Use of
inputStream = new BufferedReader(new FileReader("Crime.csv"));
System.out.println("Crime.csv contents");
// Read one Line using BufferedReader
while ((fileLine = inputStream.readLine()) != null) {
System.out.println(fileLine);
}
}
// Method to calculates number of rows in data file
private static int countRows(String dataFile) {
String fileLine;
BufferedReader inputStream = null;
int rowCount = 0;
try {
// Count rows in file
inputStream = new BufferedReader(new FileReader("Crime.csv"));
while ((fileLine = inputStream.readLine()) != null) {
rowCount++;
} // End While
} // End Try
catch (IOException io) {
System.out.println("File IO Exception" + io.getMessage());
} // End Catch
finally {
// Need another catch for closing streams
try {
// Close the streams
if (inputStream != null) {
inputStream.close();
} // End If
} // End Try
catch (IOException io) {
System.out.println("Issue closing the Files" + io.getMessage());
} // End Catch
} // End Finally
return rowCount;
} // End countRows
// getPopulationGrowth
public void getPopulationGrowth() {
for (int i = 0; i < (crimes.length - 2); i++) {
System.out.printf("\n%d - %d: %.4f%%", crimes[i].getYear(), crimes[i + 1].getYear(),
((crimes[i + 1].getPopulation() - crimes[i].getPopulation()) / (float) crimes[i].getPopulation()) * 100);
} // End For
} // End getPopulationGrowth
// getMaxViolentCrimeRate
public int getMaxViolentCrimeRate() {
double violentCrimeRate = crimes[0].getViolentCrimeRate();
double max;
int i;
// Define max value
max = violentCrimeRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (violentCrimeRate > max) {
max = violentCrimeRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxViolentCrimeRate
// getMinViolentCrimeRate
public int getMinViolentCrimeRate() {
double violentCrimeRate = crimes[0].getViolentCrimeRate();
double min;
int i;
// Define min value
min = violentCrimeRate;
// Loop to find min value
for (i = 0; i > crimes.length; i++) {
if (violentCrimeRate < min) {
min = violentCrimeRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinViolentCrimeRate
// getMaxMurderRate
public int getMaxMurderRate() {
double murderRate = crimes[0].getMurderRate();
double max;
int i;
// Define max value
max = murderRate;
// Loop to find max value
for (i = 0; i <= (crimes.length - 2); i++) {
if (murderRate > max) {
max = murderRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxMurderRate
// getMinMurderRate
public int getMinMurderRate() {
double murderRate = crimes[0].getMurderRate();
double min;
int i;
// Define max value
min = murderRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (murderRate < min) {
min = murderRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinMurderRate
// getMaxRapeRate
public int getMaxRapeRate() {
double rapeRate = crimes[0].getRapeRate();
double max;
int i;
// Define max value
max = rapeRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (rapeRate > max) {
max = rapeRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxRapeRate
// getMinRapeRate
public int getMinRapeRate() {
double rapeRate = crimes[0].getRapeRate();
double min;
int i;
// Define max value
min = rapeRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (rapeRate < min) {
min = rapeRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinRapeRate
// getMaxRobberyRate
public int getMaxRobberyRate() {
double robberyRate = crimes[0].getRobberyRate();
double max;
int i;
// Define max value
max = robberyRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (robberyRate > max) {
max = robberyRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxRobberyRate
// getMinRobberyRate
public int getMinRobberyRate() {
double robberyRate = crimes[0].getRobberyRate();
double min;
int i;
// Define max value
min = robberyRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (robberyRate < min) {
min = robberyRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinRobberyRate
// getMaxAggravatedAssaultRate
public int getMaxAggravatedAssaultRate() {
double aggravatedAssaultRate = crimes[0].getAggravatedAssaultRate();
double max;
int i;
// Define max value
max = aggravatedAssaultRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (aggravatedAssaultRate > max) {
max = aggravatedAssaultRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxAggravatedAssaultRate
// getMinAggravatedAssaultRate
public int getMinAggravatedAssaultRate() {
double aggravatedAssaultRate = crimes[0].getAggravatedAssaultRate();
double min;
int i;
// Define max value
min = aggravatedAssaultRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (aggravatedAssaultRate < min) {
min = aggravatedAssaultRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinAggravatedAssaultRate
// getMaxPropertyCrimeRate
public int getMaxPropertyCrimeRate() {
double propertyCrimeRate = crimes[0].getPropertyCrimeRate();
double max;
int i;
// Define max value
max = propertyCrimeRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (propertyCrimeRate > max) {
max = propertyCrimeRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxPropertyCrimeRate
// getMinPropertyCrimeRate
public int getMinPropertyCrimeRate() {
double propertyCrimeRate = crimes[0].getPropertyCrimeRate();
double min;
int i;
// Define max value
min = propertyCrimeRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (propertyCrimeRate < min) {
min = propertyCrimeRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinPropertyCrimeRate
// getMaxBurglaryRate
public int getMaxBurglaryRate() {
double burglaryRate = crimes[0].getBurglaryRate();
double max;
int i;
// Define max value
max = burglaryRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (burglaryRate > max) {
max = burglaryRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxBurglaryRate
// getMinBurglaryRate
public int getMinBurglaryRate() {
double burglaryRate = crimes[0].getBurglaryRate();
double min;
int i;
// Define max value
min = burglaryRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (burglaryRate < min) {
min = burglaryRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinBurglaryRate
// getMaxLarcenyTheftRate
public int getMaxLarcenyTheftRate() {
double larcenyTheftRate = crimes[0].getLarcenyTheftRate();
double max;
int i;
// Define max value
max = larcenyTheftRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (larcenyTheftRate > max) {
max = larcenyTheftRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxLarcenyTheftRate
// getMinLarcenyTheftRate
public int getMinLarcenyTheftRate() {
double larcenyTheftRate = crimes[0].getLarcenyTheftRate();
double min;
int i;
// Define max value
min = larcenyTheftRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (larcenyTheftRate < min) {
min = larcenyTheftRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinLarcenyTheftRate
// getMaxMotorVehicleTheftRate
public int getMaxMotorVehicleTheftRate() {
double motorVehicleTheftRate = crimes[0].getMotorVehicleTheftRate();
double max;
int i;
// Define max value
max = motorVehicleTheftRate;
// Loop to find max value
for (i = 0; i <= crimes.length; i++) {
if (motorVehicleTheftRate > max) {
max = motorVehicleTheftRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMaxMotorVehicleTheftRate
// getMinMotorVehicleTheftRate
public int getMinMotorVehicleTheftRate() {
double motorVehicleTheftRate = crimes[0].getMotorVehicleTheftRate();
double min;
int i;
// Define max value
min = motorVehicleTheftRate;
// Loop to find max value
for (i = 0; i > crimes.length; i++) {
if (motorVehicleTheftRate < min) {
min = motorVehicleTheftRate;
} // End If
} // End For
return crimes[i].getYear();
} // End getMinMotorVehicleTheftRate
// toString
public String toString() {
return Arrays.toString(this.crimes);
}
} // End Class
答案 0 :(得分：0)
这是一个工作版本。我已经从您的代码中重写了有问题的/需要修复的部分。请注意，我使用Java 8流和lambda来保持代码简洁。
Crimes.csv 应该看起来如下所示，但是从您的代码中，我想您拥有1994年至2013年期间的年度数据
year,population,violentCrime,violentCrimeRate,murder,murderRate,rape,rapeRate,robbery,robberyRate,aggravatedAssault,aggravatedAssaultRate,propertyCrime,propertyCrimeRate,burglary,burglaryRate,larcenyTheft,larcenyTheftRate,motorVehicleTheft,motorVehicleTheftRate
2001,2000,20,0.01,30,0.001,25,0.012,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01
2002,20100,20,0.01,30,0.001,25,0.012,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01
2003,20500,20,0.01,30,0.001,25,0.012,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01
2004,21050,20,0.01,30,0.001,25,0.012,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01,20,0.01
CrimeDataClass.java
package crimedata;
public class CrimeDataClass {
// Variable for the class
private int year = 1994;
private int population = 0;
private int violentCrime = 0;
private double violentCrimeRate = 0.0;
private int murder = 0;
private double murderRate = 0.0;
private int rape = 0;
private double rapeRate = 0.0;
private int robbery = 0;
private double robberyRate = 0.0;
private int aggravatedAssault = 0;
private double aggravatedAssaultRate = 0.0;
private int propertyCrime = 0;
private double propertyCrimeRate = 0.0;
private int burglary = 0;
private double burglaryRate = 0.0;
private int larcenyTheft = 0;
private double larcenyTheftRate = 0.0;
private int motorVehicleTheft = 0;
private double motorVehicleTheftRate = 0.0;
// Default constructor
public CrimeDataClass() {
} // End Constructor
// Full Parameterize Constructor
public CrimeDataClass(int year, int population, int violentCrime, double violentCrimeRate, int murder,
double murderRate, int rape, double rapeRate, int robbery, double robberyRate, int aggravatedAssault,
double aggravatedAssaultRate, int propertyCrime, double propertyCrimeRate, int burglary,
double burglaryRate, int larcenyTheft, double larcenyTheftRate, int motorVehicleTheft,
double motorVehicleTheftRate) {
this.year = year;
this.population = population;
this.violentCrime = violentCrime;
this.violentCrimeRate = violentCrimeRate;
this.murder = murder;
this.murderRate = murderRate;
this.rape = rape;
this.rapeRate = rapeRate;
this.robbery = robbery;
this.robberyRate = robberyRate;
this.aggravatedAssault = aggravatedAssault;
this.aggravatedAssaultRate = aggravatedAssaultRate;
this.propertyCrime = propertyCrime;
this.propertyCrimeRate = propertyCrimeRate;
this.burglary = burglary;
this.burglaryRate = burglaryRate;
this.larcenyTheft = larcenyTheft;
this.larcenyTheftRate = larcenyTheftRate;
this.motorVehicleTheft = motorVehicleTheft;
this.motorVehicleTheftRate = motorVehicleTheftRate;
} // End Constructor
// Getter Method
public int getYear() {
return this.year;
}
public int getPopulation() {
return this.population;
}
public int getViolentCrime() {
return this.violentCrime;
}
public double getViolentCrimeRate() {
return this.violentCrimeRate;
}
public int getMurder() {
return this.murder;
}
public double getMurderRate() {
return this.murderRate;
}
public int getRape() {
return this.rape;
}
public double getRapeRate() {
return this.rapeRate;
}
public int getRobbery() {
return this.robbery;
}
public double getRobberyRate() {
return this.robberyRate;
}
public int getAggravatedAssault() {
return this.aggravatedAssault;
}
public double getAggravatedAssaultRate() {
return this.aggravatedAssaultRate;
}
public int getPropertyCrime() {
return this.propertyCrime;
}
public double getPropertyCrimeRate() {
return this.propertyCrimeRate;
}
public int getBurglary() {
return this.burglary;
}
public double getBurglaryRate() {
return this.burglaryRate;
}
public int getLarcenyTheft() {
return this.larcenyTheft;
}
public double getLarcenyTheftRate() {
return this.larcenyTheftRate;
}
public int getMotorVehicleTheft() {
return this.motorVehicleTheft;
}
public double getMotorVehicleTheftRate() {
return this.motorVehicleTheftRate;
} // End Getter Method
// Setter Method
// Objects are unchangeable due to using values from CSV
// toString Method
public String toString() {
return String.format(
"\nYear: %d" + "\nPopulation: %d" + "\nViolent Crime: %d" + "\nViolent Crime Rate: %.2f"
+ "\nMurder: %d" + "\nMurder Rate: %.2f" + "\nRape: %d" + "\nRape Rate: %.2f" + "\nRobbery: %d"
+ "\nRobbery Rate: %.2f" + "\nAggravated Assault: %d" + "\nAggravated Assault Rate: %.2f"
+ "\nProperty Crime: %d" + "\nProperty Crime Rate: %.2f" + "\nBurglary: %d"
+ "\nBurglary Rate: %.2f" + "\nLarceny-Theft: %d" + "\nLarceny-Theft Rate: %.2f"
+ "\nMotor Vehicle Theft: %d" + "\nMotor Vehicle Theft Rate: %.2f",
this.year, this.population, this.violentCrime, this.violentCrimeRate, this.murder, this.murderRate,
this.rape, this.rapeRate, this.robbery, this.robberyRate, this.aggravatedAssault,
this.aggravatedAssaultRate, this.propertyCrime, this.propertyCrimeRate, this.burglary,
this.burglaryRate, this.larcenyTheft, this.larcenyTheftRate, this.motorVehicleTheft,
this.motorVehicleTheftRate);
} // End toString Method
} // End Class
CrimeDataArray.java
package crimedata;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Comparator;
import java.util.stream.Collectors;
public class CrimeDataArray {
private CrimeDataClass[] crimes;
private boolean isFileRead;
private String fileLocation;
public CrimeDataArray() {
this.fileLocation = "<add-the-full-path-to-Crimes.csv>";
}
public CrimeDataArray(String fileLocation) {
this.fileLocation = fileLocation;
}
public void readFile() {
try {
this.crimes =
Files.readAllLines(Paths.get(fileLocation))
.stream().skip(1).map(line -> line.split(","))
.map(tokens -> new CrimeDataClass(
Integer.parseInt(tokens[0]),
Integer.parseInt(tokens[1]),
Integer.parseInt(tokens[2]),
Double.parseDouble(tokens[3]),
Integer.parseInt(tokens[4]),
Double.parseDouble(tokens[5]),
Integer.parseInt(tokens[6]),
Double.parseDouble(tokens[7]),
Integer.parseInt(tokens[8]),
Double.parseDouble(tokens[9]),
Integer.parseInt(tokens[10]),
Double.parseDouble(tokens[11]),
Integer.parseInt(tokens[12]),
Double.parseDouble(tokens[13]),
Integer.parseInt(tokens[14]),
Double.parseDouble(tokens[15]),
Integer.parseInt(tokens[16]),
Double.parseDouble(tokens[17]),
Integer.parseInt(tokens[18]),
Double.parseDouble(tokens[19])
))
.collect(Collectors.toList()).toArray(new CrimeDataClass[0])
;
isFileRead = true;
} catch (IOException e) {
throw new RuntimeException("CSV file read failed, error: "+e.getMessage(), e);
}
}
public int countRows(String dataFile) {
if(!isFileRead) {
throw new RuntimeException("Data not loaded yet, call readFile() first");
}// you can use this in all methods if you wish a safety net against NullPointerException
return crimes.length;
}
// getPopulationGrowth
public void getPopulationGrowth() {
/* Gro: not changed */
for (int i = 0; i < (crimes.length - 2); i++) {
System.out.printf("\n%d - %d: %.4f%%", crimes[i].getYear(), crimes[i + 1].getYear(),
((crimes[i + 1].getPopulation() - crimes[i].getPopulation()) / (float) crimes[i].getPopulation())
* 100);
} // End For
} // End getPopulationGrowth
// getMaxViolentCrimeRate
public int getMaxViolentCrimeRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getViolentCrimeRate))
.get().getYear();
} // End getMaxViolentCrimeRate
// getMinViolentCrimeRate
public int getMinViolentCrimeRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getViolentCrimeRate))
.get().getYear();
} // End getMinViolentCrimeRate
// getMaxMurderRate
public int getMaxMurderRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getMurderRate))
.get().getYear();
} // End getMaxMurderRate
// getMinMurderRate
public int getMinMurderRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getMurderRate))
.get().getYear();
} // End getMinMurderRate
// getMaxRapeRate
public int getMaxRapeRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getRapeRate))
.get().getYear();
} // End getMaxRapeRate
// getMinRapeRate
public int getMinRapeRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getRapeRate))
.get().getYear();
} // End getMinRapeRate
// getMaxRobberyRate
public int getMaxRobberyRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getRobberyRate))
.get().getYear();
} // End getMaxRobberyRate
// getMinRobberyRate
public int getMinRobberyRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getRobberyRate))
.get().getYear();
} // End getMinRobberyRate
// getMaxAggravatedAssaultRate
public int getMaxAggravatedAssaultRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getAggravatedAssault))
.get().getYear();
} // End getMaxAggravatedAssaultRate
// getMinAggravatedAssaultRate
public int getMinAggravatedAssaultRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getAggravatedAssault))
.get().getYear();
} // End getMinAggravatedAssaultRate
// getMaxPropertyCrimeRate
public int getMaxPropertyCrimeRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getPropertyCrimeRate))
.get().getYear();
} // End getMaxPropertyCrimeRate
// getMinPropertyCrimeRate
public int getMinPropertyCrimeRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getPropertyCrimeRate))
.get().getYear();
} // End getMinPropertyCrimeRate
// getMaxBurglaryRate
public int getMaxBurglaryRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getBurglaryRate))
.get().getYear();
} // End getMaxBurglaryRate
// getMinBurglaryRate
public int getMinBurglaryRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getBurglaryRate))
.get().getYear();
} // End getMinBurglaryRate
// getMaxLarcenyTheftRate
public int getMaxLarcenyTheftRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getLarcenyTheftRate))
.get().getYear();
} // End getMaxLarcenyTheftRate
// getMinLarcenyTheftRate
public int getMinLarcenyTheftRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getLarcenyTheftRate))
.get().getYear();
} // End getMinLarcenyTheftRate
// getMaxMotorVehicleTheftRate
public int getMaxMotorVehicleTheftRate() {
return Arrays.stream(crimes)
.max(Comparator.comparing( CrimeDataClass::getMotorVehicleTheftRate))
.get().getYear();
}
public int getMinMotorVehicleTheftRate() {
return Arrays.stream(crimes)
.min(Comparator.comparing( CrimeDataClass::getMotorVehicleTheftRate))
.get().getYear();
}
// toString
public String toString() {
return Arrays.toString(this.crimes);
}
public static void main(String[] args) {
CrimeDataArray array = new CrimeDataArray();
array.readFile();
for(CrimeDataClass crime: array.crimes) {
System.out.println(crime);
}
}
} // End Class
TestCrimeData.java
package crimedata;
import java.time.Duration;
import java.time.Instant;
import java.util.Scanner;
public class TestCrimeData {
public static void main(String[] args) {
// Start time
Instant start = Instant.now();
CrimeDataArray myCrimes = null;
if(args != null && args.length > 0) {
myCrimes = new CrimeDataArray(args[0]);
}else {
myCrimes = new CrimeDataArray();
}
myCrimes.readFile();
menu(myCrimes);
// End time
Instant end = Instant.now();
System.out.println("Elapsed time (seconds): " + Duration.between(start, end).toNanos() / 1_000_000_000.0);
} // End Main
private static void menu(CrimeDataArray crimes) {
// Interaction with data
Scanner scannerIn = new Scanner(System.in);
System.out.println("********** Welcome to the US Crime Statistical Application **************************");
while (true) {
System.out.println("");
System.out.println("\nEnter the number of the question you want answered. Enter ‘Q’ to quit the program.\n"
+ "\n1. What were the percentages in population growth for each consecutive year from 1994 – 2013?"
+ "\n2. What year had the highest Violent crime rate?"
+ "\n3. What year had the lowest Violent crime rate?"
+ "\n4. What year had the highest Murder rate?" + "\n5. What year had the lowest Murder rate?"
+ "\n6. What year had the highest Robbery rate?" + "\n7. What year had the lowest Robbery rate?"
+ "\n8. What year had the highest Rape rate?" + "\n9. What year had the lowest Rape rate?"
+ "\n10. What year had the highest Aggravated Assault rate?"
+ "\n11. What year had the lowest Aggravated Assault rate?"
+ "\n12. What year had the highest Property crime rate?"
+ "\n13. What year had the lowest Property crime rate?"
+ "\n14. What year had the highest Burglary rate?"
+ "\n15. What year had the lowest Burglary rate?"
+ "\n16. What year had the highest Larceny theft rate?"
+ "\n17. What year had the lowest Larceny theft rate?"
+ "\n18. What year had the highest Motor Vehicle theft rate?"
+ "\n19. What year had the lowest Motor Vehicle theft rate?"
+ "\n20. What are the total crimes commited for each year from 1994 – 2013?" + "\nQ. Quit program."
+ "\nEnter your selection:");
// Read next line
String selection = scannerIn.nextLine().trim().toUpperCase();
if (selection.equalsIgnoreCase("Q")) {
System.out.println("Thank you for trying the US Crimes Statistics Program.");
// End loop when Q is entered
break;
} // End If
else {
switch (selection) {
case "1":
crimes.getPopulationGrowth();
break;
case "2":
System.out.printf("The Violent Crime rate was highest in %d", crimes.getMaxViolentCrimeRate());
break;
case "3":
System.out.printf("The Violent Crime rate was lowest in %d", crimes.getMinViolentCrimeRate());
break;
case "4":
System.out.printf("The Murder rate was highest in %d", crimes.getMaxMurderRate());
break;
case "5":
System.out.printf("The Murder rate was lowest in %d", crimes.getMinMurderRate());
break;
case "6":
System.out.printf("The Rape rate was highest in %d", crimes.getMaxRapeRate());
break;
case "7":
System.out.printf("The Rape rate was lowest in %d", crimes.getMinRapeRate());
break;
case "8":
System.out.printf("The Robbery rate was highest in %d", crimes.getMaxRobberyRate());
break;
case "9":
System.out.printf("The Robbery rate was lowest in %d", crimes.getMinRobberyRate());
break;
case "10":
System.out.printf("The Aggravated Assault rate was highest in %d",
crimes.getMaxAggravatedAssaultRate());
break;
case "11":
System.out.printf("The Aggravated Assault rate was lowest in %d",
crimes.getMinAggravatedAssaultRate());
break;
case "12":
System.out.printf("The Aggravated Assault rate was highest in %d",
crimes.getMaxPropertyCrimeRate());
break;
case "13":
System.out.printf("The Aggravated Assault rate was lowest in %d", crimes.getMinPropertyCrimeRate());
break;
case "14":
System.out.printf("The Burglary rate was highest in %d", crimes.getMaxBurglaryRate());
break;
case "15":
System.out.printf("The Burglary rate was lowest in %d", crimes.getMinBurglaryRate());
break;
case "16":
System.out.printf("The Larceny theft was rate was highest in %d", crimes.getMaxLarcenyTheftRate());
break;
case "17":
System.out.printf("The Larceny theft was lowest in %d", crimes.getMinLarcenyTheftRate());
break;
case "18":
System.out.printf("The Motor Vehicle theft was rate was highest in %d",
crimes.getMaxMotorVehicleTheftRate());
break;
case "19":
System.out.printf("The Motor Vehicle theft was lowest in %d", crimes.getMinMotorVehicleTheftRate());
case "20":
System.out.println(crimes.toString());
break;
default:
System.out.println("Invalid selection. Please try again.");
break;
} // End Switch
} // End Else
} // End While
scannerIn.close();
} // End Menu
} // End Class
答案 1 :(得分：-1)
只需替换行
即可解决编译问题CrimeDataClass myCrimes = new CrimeDataClass();
与
CrimeDataArray myCrimes = new CrimeDataArray();
由于您没有对要实现的目标进行太多解释，因此很难说您是否会实现自己的目标。我看到您在CrimeDataArray中具有readFile（）函数。在将对象传递给菜单方法 menu（crimes） 之前，您不应该调用它来填充 myCrimes 吗？