我试图写入一个文本文件,该文件只包含我计划稍后处理的大块文本。我必须处理的各种变量组合以及全部输入都太繁琐了。我已经尝试过两次运行此代码,它所做的就是一遍又一遍地覆盖第一行,为我提供最后一组变量。这是代码。
import java.util.*;
import java.io.*;
public class FileWritingThing {
public static void main(String[]args) throws IOException{
String precision = null;
String criteria = null;
String specLevel = null;
String precondLevel = null;
PrintWriter writer = null;
for(int i = 0; i < 3; i++){
if(i == 0){
precision = "Precision = 4;";
}
if(i == 1){
precision = "Precision = 8;";
}
if(i == 2){
precision = "Precision = 12;";
}
for(int j = 0; j < 3; j++){
if(j == 0){
criteria = "Objective Function;";
}
if(j == 1){
criteria = "Domain;";
}
if(j == 2){
criteria = "Objective Function + Domain;";
}
for(int k = 0; k < 3; k++){
if(k == 0){
specLevel = "Speculation Level = 10000;";
}
if(k == 1){
specLevel = "Speculation Level = 100000;";
}
if(k == 2){
specLevel = "Speculation Level = 1000000;";
}
for(int l = 0; l < 3; l++){
if(l == 0){
precondLevel = "Precondition Level = 0;";
}
if(l == 1){
precondLevel = "Precondition Level = 25;";
}
if(l == 2){
precondLevel = "Precondition Level = 100;";
}
writer.println(precision + "\n" + criteria + "\n" + specLevel + "\n" + precondLevel + "\n");
}
}
}
}
writer.close();
}
}
/*try {
writer = new PrintWriter(new BufferedWriter(new FileWriter("permutations.txt", true)));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
*/
我需要知道的是如何将每个块附加到文件行。另外,即使我已经包含&#34; \ n&#34;我也会遇到一些奇怪的问题。为了分离变量列表,无论如何都显示在一行上。底部的注释代码最初包含在&#34; writer.println()&#34;之前。线。
答案 0 :(得分:1)
如果注释行位于writer.println()的上方,那么它可能会解释您遇到的奇怪行为。您应该在for循环外创建PrintWriter。像这样的东西
PrintWriter writer = null;
try {
writer = new PrintWriter(new BufferedWriter(new FileWriter("permutations.txt", true)));
// Most outer for loop goes here
for(int i=0......) {
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch(Exception e) { e.printStackTrace(); }
finally {
if(writer!=null) {
try {
writer.flush();
writer.close();
} catch(Exception ignore) {}
}
}