My code uses a buffered reader to read a file with a list of values, and my FileWriter adds another gamer to the list. Whenever I go to run my code, the new gamer is added repeatedly. How do I read the data into memory and then write the memory back into the file without the last line added?
Input:
package week3assignment;
import java.io.*;
import java.util.Scanner;
public class Jaret_Dalrymple_GamesReport {
public static void main(String[] args) throws IOException {
File gameScores = new File("C:\\Users\\jaret\\OneDrive\\Desktop\\GameScores.csv");
readWrite(gameScores);
addGamer(gameScores, "Jimmy", "189", "190", "197", "199", "198", "193", "199", "199", "188", "196");
readWrite2(gameScores);
}
private static void readWrite(File gameScores) throws IOException {
if (gameScores.exists()) {
BufferedReader br = null;
String line = "";
String csvSplitBy = ",";
int gamerCount = 0;
int topScore = 0;
String topScorer = "";
br = new BufferedReader(new FileReader(gameScores));
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
System.out.println("Games Report");
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
System.out.println("Gamer 1 2 3 4 5 6 7");
System.out.println(" 8 9 10 Total");
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
while ((line = br.readLine()) != null) {
String list[] = new String[10];
list = line.split(csvSplitBy);
int sum = 0;
for (String element : list) {
try {
Integer num = Integer.parseInt(element);
sum = num;
} catch (NumberFormatException nfe) {
System.out.print(list[0] "\t" list[1] (list[1].length() > 10 ? "\t" : "\t") list[2]
(list[2].length() > 10 ? "\t" : "\t") list[3]
(list[3].length() > 10 ? "\t" : "\t") list[4]
(list[4].length() > 10 ? "\t" : "\t") list[5]
(list[5].length() > 10 ? "\t" : "\t") list[6]
(list[6].length() > 10 ? "\t" : "\t") list[7]
(list[7].length() > 10 ? "\n\t" : "\n\t") list[8]
(list[8].length() > 10 ? "\t" : "\t") list[9]
(list[9].length() > 10 ? "\t" : "\t") list[10] "\t");
}
}
if (sum > topScore) {
topScore = sum;
topScorer = list[0];
}
System.out.println(sum);
gamerCount ;
}
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
System.out.println("# of Gamers: " gamerCount);
System.out.println("Top Gamer: " topScorer);
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
br.close();
}
}
private static void addGamer(File gameScores, String first, String second, String third, String fourth,
String fifth, String sixth, String seventh, String eighth, String ninth, String tenth, String eleventh)
throws IOException {
FileWriter newGamer = new FileWriter(gameScores, true);
newGamer.write("\n" first "," second "," third "," fourth "," fifth "," sixth ","
seventh "," eighth "," ninth "," tenth "," eleventh);
newGamer.close();
System.out.println("Gamer Jimmy record added.");;
}
private static void readWrite2(File gameScores) throws IOException {
if (gameScores.exists()) {
BufferedReader br = null;
String line = "";
String csvSplitBy = ",";
int gamerCount = 0;
int topScore = 0;
String topScorer = "";
FileWriter fw = new FileWriter(gameScores, true);
br = new BufferedReader(new FileReader(gameScores));
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
System.out.println("Games Report");
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
System.out.println("Gamer 1 2 3 4 5 6 7");
System.out.println(" 8 9 10 Total");
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
while ((line = br.readLine()) != null) {
String list[] = new String[10];
list = line.split(csvSplitBy);
int sum = 0;
for (String element : list) {
try {
Integer num = Integer.parseInt(element);
sum = num;
} catch (NumberFormatException nfe) {
System.out.print(list[0] "\t" list[1] (list[1].length() > 10 ? "\t" : "\t") list[2]
(list[2].length() > 10 ? "\t" : "\t") list[3]
(list[3].length() > 10 ? "\t" : "\t") list[4]
(list[4].length() > 10 ? "\t" : "\t") list[5]
(list[5].length() > 10 ? "\t" : "\t") list[6]
(list[6].length() > 10 ? "\t" : "\t") list[7]
(list[7].length() > 10 ? "\n\t" : "\n\t") list[8]
(list[8].length() > 10 ? "\t" : "\t") list[9]
(list[9].length() > 10 ? "\t" : "\t") list[10] "\t");
}
}
if (sum > topScore) {
topScore = sum;
topScorer = list[0];
}
System.out.println(sum);
gamerCount ;
}
System.out.println("----------------------------------------------------------");
System.out.println("-------------------------------------");
System.out.println("# of Gamers: " gamerCount);
System.out.println("Top Gamer: " topScorer);
br.close();
}
}
}
Ouput:
----------------------------------------------------------
-------------------------------------
Games Report
----------------------------------------------------------
-------------------------------------
Gamer 1 2 3 4 5 6 7
8 9 10 Total
----------------------------------------------------------
-------------------------------------
Bob 167 123 159 102 102 189 183
173 197 148 1543
Sally 189 130 138 113 159 116 134
196 150 144 1469
Mario 104 106 120 188 143 189 149
174 163 100 1436
Lev 152 159 195 140 154 176 107
128 166 181 1558
Carden 158 200 175 114 117 150 176
181 131 132 1534
Adelie 175 199 122 104 198 182 175
153 120 165 1593
Lada 161 108 102 193 151 197 115
137 126 186 1476
Xavier 178 171 147 113 107 129 128
189 165 195 1522
Raffi 176 144 151 124 149 112 158
159 119 177 1469
Chang 135 144 177 153 143 125 145
140 117 158 1437
Mich 156 105 178 137 165 180 128
115 139 157 1460
Mason 162 185 108 106 113 135 139
135 197 160 1440
Cora 186 115 106 126 135 108 157
156 187 120 1396
Sergio 117 105 115 116 193 200 176
134 122 153 1431
Jonas 132 163 196 101 134 159 131
104 135 168 1423
Jimmy 189 190 197 199 198 193 199
199 188 196 1948
----------------------------------------------------------
-------------------------------------
# of Gamers: 16
Top Gamer: Jimmy
----------------------------------------------------------
-------------------------------------
Gamer Jimmy record added.
----------------------------------------------------------
-------------------------------------
Games Report
----------------------------------------------------------
-------------------------------------
Gamer 1 2 3 4 5 6 7
8 9 10 Total
----------------------------------------------------------
-------------------------------------
Bob 167 123 159 102 102 189 183
173 197 148 1543
Sally 189 130 138 113 159 116 134
196 150 144 1469
Mario 104 106 120 188 143 189 149
174 163 100 1436
Lev 152 159 195 140 154 176 107
128 166 181 1558
Carden 158 200 175 114 117 150 176
181 131 132 1534
Adelie 175 199 122 104 198 182 175
153 120 165 1593
Lada 161 108 102 193 151 197 115
137 126 186 1476
Xavier 178 171 147 113 107 129 128
189 165 195 1522
Raffi 176 144 151 124 149 112 158
159 119 177 1469
Chang 135 144 177 153 143 125 145
140 117 158 1437
Mich 156 105 178 137 165 180 128
115 139 157 1460
Mason 162 185 108 106 113 135 139
135 197 160 1440
Cora 186 115 106 126 135 108 157
156 187 120 1396
Sergio 117 105 115 116 193 200 176
134 122 153 1431
Jonas 132 163 196 101 134 159 131
104 135 168 1423
Jimmy 189 190 197 199 198 193 199
199 188 196 1948
Jimmy 189 190 197 199 198 193 199
199 188 196 1948
----------------------------------------------------------
-------------------------------------
# of Gamers: 17
Top Gamer: Jimmy
CodePudding user response：
When you have a while loop with this condition:
line = br.readLine() != null
You could change it to something like this:
line = br.readLine();
while(line != null){
your code here...
} // end loop
You could make a temporary variable to store the line you're using on the loop, and in case the code exits finally the loop, get that line and delete it from the csv.
PS: Sorry if I didn't explain myself as good as I would like, just starting on this. Good luck!
CodePudding user response：
A most basic example of writing data from an ArrayList:
public static void main(String[] args) throws Exception
{
ArrayList<String> lines = new ArrayList<>();
lines.add("one");
lines.add("two");
lines.add("three");
File file = new File("testing.txt");
BufferedWriter writer = new BufferedWriter( new FileWriter( file ) );
for (int i = 0; i < lines.size(); i )
{
if (i > 0)
writer.newLine();
writer.write( lines.get(i) );
}
writer.close();
}
So you first need to read your data into the ArrayList and delete the last item before writing out the data in the ArrayList.