左边是我的代码在eclipse内部运行，您可以看到数据已添加到JComboBox，而右边是我的代码作为可导出jar文件运行。数据未运行。
下面是我对Predictor类内部文件代码的读写操作。
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.TreeSet;
public class Predictor {
/*
* This class manages two collections of Day objects
* allows for adding new days
* allows for predicting unknown days.
*/
private TreeSet<Day> myData; // data organized by Day's compareTo method incorportate yes, no and maybe for data
private ArrayList<Day> orginalData; // original data with no changes to class value. set by file and adding days
private String fileName;
public Predictor() {
myData = new TreeSet<Day>();
orginalData = new ArrayList<Day>();
fileName = null;
}
public Predictor(String fn) {
this(); // call the default constructor to instantiate the TreeSet
fileName = fn;
readFile();
}
public String predict (Day d) {
Day closestFloor = myData.floor(d);
Day closestCeiling = myData.ceiling(d);
if (closestFloor == null && closestCeiling == null)
return "yes";
if (closestFloor != null && closestFloor.equals(d)) { // found an exact match
if (closestFloor.getPlayTennis().equals("no"))
return "no";
else
return "yes"; //manages both yes and maybe
}
if (closestCeiling != null && closestCeiling.equals(d)) { // found an exact match
if (closestCeiling.getPlayTennis().equals("no"))
return "no";
else
return "yes"; //manages both yes and maybe
}
if (closestFloor != null && closestCeiling == null) {
if( closestFloor.getPlayTennis().equals("no"))
return "no";
else
return "yes"; // closestFloor could have been maybe
}
if (closestFloor == null && closestCeiling != null) {
if( closestCeiling.getPlayTennis().equals("no"))
return "no";
else
return "yes"; // closestCeiling could have been maybe
}
// if I get here both are not null.
// if both are no, predict no.
if (closestFloor.getPlayTennis().equals("no") && closestCeiling.getPlayTennis().equals("no"))
return "no";
return "yes";
}
public void addDay (Day d) {
orginalData.add(new Day(d.getOutlook(),d.getTemp(),d.getHumidity(),d.getWindy(),d.getPlayTennis())); // maintain unmodified data for training error
// when adding a day, if a similar day exists by the compareTo definition modify the existing
// day as follows
// if they agree, keep the same
// if existing is yes and new is no make maybe
// if existing is maybe and new is no make no
// if existing is maybe and new is yes make yes
// if existing is no and new is yes make maybe
Day closestDay = myData.floor(d);
if (closestDay == null || !closestDay.equals(d)) {
myData.add(d);
return;
}
if (closestDay.getPlayTennis().equals(d.getPlayTennis()))
return; // they agree
if (closestDay.getPlayTennis().equals("yes") && d.getPlayTennis().equals("no")) {
closestDay.setPlayTennis("maybe");
}
else if (closestDay.getPlayTennis().equals("maybe") && d.getPlayTennis().equals("no"))
closestDay.setPlayTennis("no");
else if (closestDay.getPlayTennis().equals("maybe") && d.getPlayTennis().equals("yes"))
closestDay.setPlayTennis("yes");
else if (closestDay.getPlayTennis().equals("no") && d.getPlayTennis().equals("yes")) {
closestDay.setPlayTennis("maybe");
}
}
public double trainingError () {
// test the predictive ability on all of the data
int count = 0;
for (Day d:orginalData) {
String thisPrediction = predict (d);
if (thisPrediction.equals(d.getPlayTennis()))
count++;
}
return (double)count/orginalData.size();
}
public String toString() {
// returns a string representation of this Predictor
String toReturn = "";
for (Day d:myData) {
toReturn += d.toString()+"\n";
}
return toReturn+"training error: "+trainingError();
}
private void readFile () {
// private method that reads the file and stores into TreeSet
BufferedReader lineReader = null;
try {
//BufferedReader lineReader = new BufferedReader(new InputStreamReader(this.getClass().getResourceAsStream(fileName)));
//FileReader fr = new FileReader(fileName);
lineReader = new BufferedReader(new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8")));
//lineReader = new BufferedReader(fr);
String line = null;
while ((line = lineReader.readLine())!=null) {
String[] tokens = line.split(",");
addDay (new Day(tokens[0],Integer.parseInt(tokens[1]),Integer.parseInt(tokens[2]),Boolean.parseBoolean(tokens[3].toLowerCase()),tokens[4]));
// orginalData.add(new Day(tokens[0],Integer.parseInt(tokens[1]),Integer.parseInt(tokens[2]),Boolean.parseBoolean(tokens[3].toLowerCase()),tokens[4]));
}
} catch (Exception e) {
e.printStackTrace();
System.err.println("there was a problem with the file. either no such file or format error");
} finally {
if (lineReader != null)
try {
lineReader.close();
} catch (IOException e) {
System.err.println("could not close BufferedReader");
System.out.println("TEST");
}
}
} // end of readFile method
public void writeFile () {
// overloaded method: this calls doWrite with file used to read data
// use this for saving data between runs
doWrite(fileName);
} // end of writeFile method
public void writeFile(String altFileName) {
// overloaded method: this calls doWrite with different file name
// use this for testing write
doWrite(altFileName);
}// end of writeFile method
private void doWrite(String fn) {
// this method writes all of the data in the persons array to a file
try
{
FileWriter fw = new FileWriter(fn);
BufferedWriter myOutfile = new BufferedWriter(fw);
for (Day d:orginalData) {
myOutfile.write(d.getOutlook()+","+d.getTemp()+","+d.getHumidity()+","+d.getWindy()+","+d.getPlayTennis()+"\n");
}
myOutfile.flush();
myOutfile.close();
}
catch (Exception e) {
e.printStackTrace();
System.err.println("Didn't save to " + fn);
}
}
}
下面是在我的MainPanel内部编写的JComboBox代码
Predictor myPred = new Predictor ("./project2/data.txt");
comboBox = new JComboBox();
comboBox.setModel(new DefaultComboBoxModel(myPred.toString().split("\n")));
comboBox.setBounds(131, 35, 262, 38);
add(comboBox);