javastring写文件

① java 写txt文件

import java.io.*;
public class Test {

public static void main(String[] args){
String s = new String();
String s1 = new String();
try {
File f = new File("E:\\123.txt");
if(f.exists()){
System.out.print("文件存在");
}else{
System.out.print("文件不存在");
f.createNewFile();//不存在则创建
}
BufferedReader input = new BufferedReader(new FileReader(f));

while((s = input.readLine())!=null){
s1 += s+"\n";
}
System.out.println(s1);
input.close();
s1 += "添加的内容!";

BufferedWriter output = new BufferedWriter(new FileWriter(f));
output.write(s1);
output.close();
} catch (Exception e) {
e.printStackTrace();
}
}

}

② java 怎么将数据写入TXT文件

import java.io.FileWriter;
import java.io.IOException;

public class Test02 {

void writefile() throws IOException {
FileWriter fileWriter=new FileWriter("c:\\Result.txt");
int [] a=new int[]{111,222,333,444,555,666};
for (int i = 0; i < a.length; i++) {
fileWriter.write(String.valueOf(a[i])+" ");

}
fileWriter.flush();
fileWriter.close();
}
public static void main(String[] args) throws IOException {
new Test02().writefile();
}
}
//你看来看，就这源两句，测试通过了！

③ java 语言中如何实现 写文件 换行。。谢谢了！！

1.\r\n就是换行了

2.然后就是楼上说的BufferedWriter的newline了

3. System.getProperty("line.separator");
给个例子给你吧
.....
1.
String s = "aaa";
s += "aaa"+"\r\n";

这样，在s之后就有换行了
2.略
3. String s = "aaa"+System.getProperty("line.separator");