我可以用Java在同一个类中编写FileWriter和bufferedwriter吗?
下面是我试图使用Filewriter编写的代码。这很好用我可以用Java在同一个类中编写FileWriter和bufferedwriter吗?,java,filewriter,bufferedwriter,Java,Filewriter,Bufferedwriter,下面是我试图使用Filewriter编写的代码。这很好用 File f2 = new File("Path"); f2.createNewFile(); FileWriter writing = new FileWriter(f2); writing.write("i'm into you , i'm into you"); writing.flush(); 在下面的代码中,我尝试使用bufferedwriter进行编写。这不是将任何文本添加到同一文件中。对于不同的文件,它是有
File f2 = new File("Path");
f2.createNewFile();
FileWriter writing = new FileWriter(f2);
writing.write("i'm into you , i'm into you");
writing.flush();
在下面的代码中,我尝试使用bufferedwriter进行编写。这不是将任何文本添加到同一文件中。对于不同的文件,它是有效的
BufferedWriter buffwrite = new BufferedWriter(writing); buffwrite.write("java");
writing.flush();
这些IO相关类是基于装饰器模式设计的 如果您参考
BufferedWriter
类javadoc,您会找到一个接受Writer
类型对象的构造函数Writer
是一个抽象类,在其他类中由FileWriter
扩展。在构造函数中传递FileWriter
对象,然后调用BufferedWriter
的write(…)
和flush
方法
所有IO类都以这种模式工作。是的您可以编写。请检查以下使用FileWriter、BufferedWriter、FileOutputStream和java文件编写java文件的用例
package com.journaldev.files;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Paths;
public class WriteFile {
/**
* This class shows how to write file in java
* @param args
* @throws IOException
*/
public static void main(String[] args) {
String data = "I will write this String to File in Java";
int noOfLines = 10000;
writeUsingFileWriter(data);
writeUsingBufferedWriter(data, noOfLines);
writeUsingFiles(data);
writeUsingOutputStream(data);
System.out.println("DONE");
}
/**
* Use Streams when you are dealing with raw data
* @param data
*/
private static void writeUsingOutputStream(String data) {
OutputStream os = null;
try {
os = new FileOutputStream(new File("/Users/pankaj/os.txt"));
os.write(data.getBytes(), 0, data.length());
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* Use Files class from Java 1.7 to write files, internally uses OutputStream
* @param data
*/
private static void writeUsingFiles(String data) {
try {
Files.write(Paths.get("/Users/pankaj/files.txt"), data.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Use BufferedWriter when number of write operations are more
* It uses internal buffer to reduce real IO operations and saves time
* @param data
* @param noOfLines
*/
private static void writeUsingBufferedWriter(String data, int noOfLines) {
File file = new File("/Users/pankaj/BufferedWriter.txt");
FileWriter fr = null;
BufferedWriter br = null;
String dataWithNewLine=data+System.getProperty("line.separator");
try{
fr = new FileWriter(file);
br = new BufferedWriter(fr);
for(int i = noOfLines; i>0; i--){
br.write(dataWithNewLine);
}
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
br.close();
fr.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* Use FileWriter when number of write operations are less
* @param data
*/
private static void writeUsingFileWriter(String data) {
File file = new File("/Users/pankaj/FileWriter.txt");
FileWriter fr = null;
try {
fr = new FileWriter(file);
fr.write(data);
} catch (IOException e) {
e.printStackTrace();
}finally{
//close resources
try {
fr.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
是的,你肯定可以在同一堂课上写。 您的代码没有向同一个文件中添加任何文本,因为您正在先刷新FileWriter,再刷新BufferedWriter。我只是编辑了你的代码如下,它工作得很好
File f2 = new File("Path");
f2.createNewFile();
FileWriter writing = new FileWriter(f2);
writing.write("i'm into you , i'm into you");
BufferedWriter buffwrite = new BufferedWriter(writing);
buffwrite.write("java");
buffwrite.flush();//flush BufferedWriter first followed by FileWriter
writing.flush();
您应该
关闭
打开的资源:FileWriter write
和BufferedWriter buffwrite
。这()
冲过小溪。如果流已从中保存任何字符
在缓冲区中的各种write()方法,立即将它们写入
预定目的地。然后,如果目标是另一个字符
或者字节流,刷新它。因此,一次flush()调用将刷新所有
写入程序和输出流链中的缓冲区
正确的方法是使用语句。这将导致关闭已打开的资源
或者使用java.nio.file.Files.write
方法来处理资源。尝试buffwrite.flush()
您正在刷新FileWriter。