总是忘记， 备份一下，方便下次用.
第一种：
File directory = new File("");//参数为空
String courseFile = directory.getCanonicalPath() ;System.out.println(courseFile);
结果：C:\Documents and Settings\Administrator\workspace\projectName获取当前类的所在工程路径;
第二种：
File f = new File(this.getClass().getResource("/").getPath());
System.out.println(f);
结果:C:\Documents and Settings\Administrator\workspace\projectName\bin
如果不加“/”
File f = new File(this.getClass().getResource("").getPath());
System.out.println(f);
结果：C:\Documents and Settings\Administrator\workspace\projectName\bin\com\test
第三种：URL xmlpath = this.getClass().getClassLoader().getResource("selected.txt");
System.out.println(xmlpath);
结果：file:/C:/Documents and Settings/Administrator/workspace/projectName/bin/selected.txt
第四种：
System.out.println(System.getProperty("user.dir"));
结果：C:\Documents and Settings\Administrator\workspace\projectName
第五种：System.out.println( System.getProperty("java.class.path"));
结果：C:\Documents and Settings\Administrator\workspace\projectName\bin
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.RandomAccessFile; public class FileOperation { /**
* 创建文件
* @param fileName
* @return
*/
public static boolean createFile(File fileName)throws Exception{
boolean flag=false;
try{
if(!fileName.exists()){
fileName.createNewFile();
flag=true;
}
}catch(Exception e){
e.printStackTrace();
}
return true;
} /**
* 读TXT文件内容
* @param fileName
* @return
*/
public static String readTxtFile(File fileName)throws Exception{
String result=null;
FileReader fileReader=null;
BufferedReader bufferedReader=null;
try{
fileReader=new FileReader(fileName);
bufferedReader=new BufferedReader(fileReader);
try{
String read=null;
while((read=bufferedReader.readLine())!=null){
result=result+read+"\r\n";
}
}catch(Exception e){
e.printStackTrace();
}
}catch(Exception e){
e.printStackTrace();
}finally{
if(bufferedReader!=null){
bufferedReader.close();
}
if(fileReader!=null){
fileReader.close();
}
}
System.out.println("读取出来的文件内容是："+"\r\n"+result);
return result;
} public static boolean writeTxtFile(String content,File fileName)throws Exception{
RandomAccessFile mm=null;
boolean flag=false;
FileOutputStream o=null;
try {
o = new FileOutputStream(fileName);
o.write(content.getBytes("GBK"));
o.close();
// mm=new RandomAccessFile(fileName,"rw");
// mm.writeBytes(content);
flag=true;
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
if(mm!=null){
mm.close();
}
}
return flag;
} public static void contentToTxt(String filePath, String content) {
String str = new String(); //原有txt内容
String s1 = new String();//内容更新
try {
File f = new File(filePath);
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 ((str = input.readLine()) != null) {
s1 += str + "\n";
}
System.out.println(s1);
input.close();
s1 += content; BufferedWriter output = new BufferedWriter(new FileWriter(f));
output.write(s1);
output.close();
} catch (Exception e) {
e.printStackTrace(); }
} }