java中的FileWriter用于创建文件，可以向创建的文件中写入字符；输出流类是 FileWriter 类的基类，因为它是从 FileWriter 类继承的，并且该类的构造函数所做的假设是，如果要由我们指定这些值，则允许默认字符编码和默认字节缓冲区大小。输出流编写器必须在文件输出流上构造。
Java FileWriter 类声明：
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Java.lang.Object Java.io.Writer Java.io.OutputStreamWriter Java.io.FileWriter
java中的FileWriter类由多个构造函数组成。他们是：
java中的FileWriter类由几个方法组成，分别是：
下面是用Java实现FileWriter的例子：
演示 FileWriter 类创建的 Java 程序。
代码：
import java.io.*;
public class Read {
public static void main(String args[])throws IOException {
File file1 = new File("check.txt");
// A file is created
file1.createNewFile();
// Object of FileWriter is created
FileWriter writer1 = new FileWriter(file1);
// Contents are written to the file
writer1.write("Welcome to FileWriter");
writer1.flush();
writer1.close();
// Object of filereader is created
FileReader read = new FileReader(file1);
char [] a1 = new char[50];
read.read(a1); // array contents are read
for(char ch : a1)
System.out.print(ch); // characters are printed one by one
read.close();
}
}输出：
使用 FileWriter 类创建文本文件的 Java 程序。
代码：
import java.io.*;
public class Example {
public static void main(String[] args) {
//File constructor is initialized
File file1 = new File("C:/Users/shivakumarsh/Desktop/Learning/source.txt");
try {
boolean create = file1.createNewFile();
if (create) {
System.out.println("File creation is succesful.");
}else {
System.out.println("There is already a file by this name.");
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
Java 程序演示将字符串附加到文件末尾。
代码：
import java.io.*;
public class Example {
public static void append(String fileName,
String string)
{
try {
// The file is opened in append mode
BufferedWriter out1 = new BufferedWriter(
new FileWriter(fileName, true));
out1.write(string);
out1.close();
}
catch (IOException e) {
System.out.println("occurance of exception" + e);
}
}
public static void main(String[] args)
throws Exception
{
// A sample file is created with some text containing in it
String fileName = "Shobha.txt";
try {
BufferedWriter out1 = new BufferedWriter(
new FileWriter(fileName));
out1.write("Learning appending\n");
out1.close();
}
catch (IOException e) {
System.out.println("occurance of exception" + e);
}
// The newly created file is appended with the string value passed here
String string = "Learning is good";
append(fileName, string);
// contents of the modified file are printed here
try {
BufferedReader in1 = new BufferedReader(
new FileReader("Shobha.txt"));
String mystr;
while ((mystr = in1.readLine()) != null) {
System.out.println(mystr);
}
}
catch (IOException e) {
System.out.println("Occurance of exception" + e);
}
}
}输出：
Java 程序使用 FileWriter 逐行写入文件。
代码：
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.List;
public class List {
public static void main(String[] args) throws Exception {
ArrayList<String> list1 = new ArrayList<String>();
// The newly created file is appended with the string value passed here
list1.add("Understanding an example in java");
list1.add("second line of the file");
list1.add("third line of the file");
writeFile("C:/Users/shivakumarsh/Desktop/Learning/source.txt", list1);
System.out.println("file creation is successful");
}
public static void write(String fileName, List<String> list1) throws Exception {
FileWriter fwd = null;
BufferedWriter bwd = null;
try {
fwd = new BufferedWriter(fwd);
for (int j = 0; list1 != null && j < list.size(); j++) {
bwd.write(list.get(j));
bwd.write("\n");
}
} catch (Exception e1) {
System.out.println("error occured:" + e1.getMessage());
throw e1;
} finally {
try {
bwd.close();
} catch (Exception e1) {
}
try {
fwd.close();
} catch (Exception e1) {
}
}
}
}输出：
在本教程中，我们了解了 FileWriter 的概念，如 FileWriter 的定义、如何声明 FileWriter、FileWriter 中的构造函数以及编程示例来演示 FileWriter 类的创建，使用 FileWriter 类创建文本文件，使用FileWriter 类将文本追加到由内容组成的现有文件中，使用 FileWriter 类逐行写入新文件，即一行一行地添加内容。
这是 Java 中 FileWriter 的指南。这里我们讨论如何声明 FileWriter、FileWriter 中的构造函数及其方法以及代码实现。您还可以浏览我们其他推荐的文章以了解更多信息 –
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