Java文件操作示例-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_29591261/article/details/77154284

代码

package fileOperation;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
public class FileOperation {
public static void main(String[] args) {
String filePath = "D:/test/test.txt";
String content = "第一行\n第二行\n";
String content2 = "第三行\n第四行\n";
createFile(filePath);
writeFile(filePath, content);
writeFile(filePath, content2);
readFile(filePath);
}
/*
*按行读取文件
*/
public static void readFile(String filePath) {
File file = new File(filePath);
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(file));
String tempString = null;
while ((tempString = reader.readLine()) != null) {
System.out.println(tempString);
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e1) {
}
}
}
}
/*
*以追加方式写文件
*/
public static void writeFile(String filePath, String conent) {
BufferedWriter out = null;
try {
out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filePath, true)));
out.write(conent);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (out != null) {
out.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
/*
*创建文件
*/
public static void createFile(String filePath) {
File file = new File(filePath);
if (file.exists()) {
//System.out.println("文件已存在");
} else {
try {
File fileParent = file.getParentFile();
if (fileParent != null) {
if (!fileParent.exists()) {
fileParent.mkdirs();
}
}
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/*
*以追加方式写文件，效率低
*/
public static void writeFileByFileWriter(String filePath, String content) {
FileWriter writer = null;
try {
writer = new FileWriter(new File(filePath), true);
writer.write(content);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (writer != null) {
writer.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}