java如何设置保存路径 java怎样保存

// 打开文件 filePath文件路径62616964757a686964616fe59b9ee7ad9431333332613739xx.txt文件名
Runtime.getRuntime().exec("notepad.exe filePath:/xx.txt");
// 保存文件 echo + 内容(sourse) + > +filePath/xx.txt
Runtime.getRuntime().exec("cmd /k echo sourse > d:/xx.txt");
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;import java.io.IOException;
public class IOTest {
public static void main(String[] args){
File f = new File("E:\\1.txt");
//读
String oldStr = "";
try {
FileReader fr = new FileReader(f);
BufferedReader br = new BufferedReader(fr);
String line = null;
while((line = br.readLine())!=null){
oldStr += line;
}
} catch (FileNotFoundException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//写
String newStr = "zxc";
FileWriter fw;
try {
fw = new FileWriter(f);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(oldStr+"\r\n"+newStr);//不想换行就把\r\n去掉
bw.close();
fw.close();
} catch (IOException e) {
e.printStackTrace();
}
} 
}