0. 字节流与二进制文件
我的代码
我的总结
1. 字符流与文本文件
我的代码
我的总结
2. 缓冲流(结合使用JUint进行测试)
我的代码
main函数:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;
import javax.swing.text.AbstractDocument.BranchElement;
public class WriteFile {
public static void main(String[] args) {
// TODO Auto-generated method stub
String fileName = "e:/bigdata.txt";
int n = 1000_0000;
Random r = new Random(100);
try (PrintWriter pWriter = new PrintWriter(fileName)){
for (int i = 0; i < n; i++) {
pWriter.println(r.nextInt(11));
}
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
}
/*try (BufferedReader br = new BufferedReader(new FileReader(new File(fileName)))){
String string = null;
int count=0;
long sum=0;
double average = 0.0;
while ((string=br.readLine())!=null) {
int num = Integer.parseInt(string);
sum+=num;
count++;
}
average=1.0*sum/count;
System.out.format("count = %d,sum = %d,averge = %.5f",count,sum,average);
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}*/
}
}
Junit:
package test;
import static org.junit.jupiter.api.Assertions.*;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
import org.junit.jupiter.api.Test;
class testRead {
String fileName = "e:/bigdata.txt";
@Test
void testB() {
try (BufferedReader br = new BufferedReader(new FileReader(new File(fileName)))){
String string = null;
int count=0;
long sum=0;
double average = 0.0;
while ((string=br.readLine())!=null) {
int num = Integer.parseInt(string);
sum+=num;
count++;
}
average=1.0*sum/count;
System.out.format("count = %d,sum = %d,averge = %.5f",count,sum,average);
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
@Test
void testS() {
try (Scanner sc = new Scanner(new File(fileName))){
String string = null;
int count=0;
long sum=0;
double average = 0.0;
while (sc.hasNextLine()) {
string = sc.nextLine();
int num = Integer.parseInt(string);
sum+=num;
count++;
}
average=1.0*sum/count;
System.out.format("count = %d,sum = %d,averge = %.5f",count,sum,average);
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
我的总结
我的代码
我的总结
我的代码
我的总结
我的代码
我的总结