J2ME 本土文件读写

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.microedition.io.Connector;
import javax.microedition.io.file.FileConnection;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.StringItem;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
/**
* 文件读写Demo
*
* @author kf156(亚日)
*
*/
public class FileOperations extends MIDlet implements CommandListener {
Form form = new Form("FileOperations");
StringBuffer sb = new StringBuffer();
String filePath = "file:///e:/1.txt";// 要读写的文件路径 索爱、诺基亚等存储卡
// String filePath = "file:///root1/1.txt";// 要读写的文件路径 模拟器
// StringItem si = new StringItem(null, "要写入的数据：");
StringItem info = new StringItem(null, null);
TextField tf = new TextField("要写入的数据", "测试", 100, TextField.ANY);
Command exit = new Command("退出", Command.EXIT, 1);
Command write = new Command("写文件", Command.OK, 1);
Command read = new Command("读文件", Command.OK, 1);
public FileOperations() {
? // form.append(si);
? form.append(tf);
? form.addCommand(write);
? form.addCommand(read);
? form.addCommand(exit);
? form.setCommandListener(this);
}
protected void destroyApp(boolean arg0) {
}
protected void pauseApp() {
}
protected void startApp() throws MIDletStateChangeException {
? Display.getDisplay(this).setCurrent(form);
}
/**
? * 添加文字
? *
? * @param str
? *??????????? 要添加的文字
? */
private void addStr(String str) {
? sb.append(str + "\n");
? info.setText(sb.toString());
}
/**
? * 写文件
? *
? * @param b
? */
private void write(byte[] b) {
? addStr("路径为" + filePath);
? write(filePath, b);
}
private void write(String path, byte[] b) {
? addStr("写文件");
? FileConnection fc = null;
? OutputStream os = null;
? try {
?? fc = (FileConnection) Connector.open(path);
?? if (!fc.exists())// 若文件不存在
??? fc.create();// 创建文件
?? else
??? fc.truncate(0);// 清空文件数据
?? os = fc.openOutputStream();
?? os.write(b);// 写入文件数据
?? os.close();
?? os = null;
?? addStr("写文件完毕");
?? fc.close();
?? fc = null;
? } catch (IOException e) {
?? e.printStackTrace();
?? addStr("写文件出现异常" + e.toString());
? } catch (SecurityException e) {
?? e.printStackTrace();
?? addStr("写文件时出现权限错误");
? } finally {
?? if (os != null) {
??? try {
???? os.close();
??? } catch (IOException e) {
???? e.printStackTrace();
??? }
??? os = null;
?? }
?? if (fc != null) {
??? try {
???? fc.close();
??? } catch (IOException e) {
???? e.printStackTrace();
??? }
??? fc = null;
?? }
? }
}
/**
? * 读文件
? *
? */
private void read() {
? addStr("路径为" + filePath);
? read(filePath);
}
private void read(String path) {
? addStr("读文件");
? FileConnection fc = null;
? InputStream is = null;
? try {
?? fc = (FileConnection) Connector.open(path);
?? if (!fc.exists()) {// 若文件不存在
??? addStr("文件不存在");
??? return;
?? }
?? is = fc.openInputStream();
?? byte[] b = new byte[(int) fc.fileSize()];
?? is.read(b);// 读出文件数据
?? addStr("文件内容：");
?? addStr(new String(b));
?? addStr("读文件完毕");
?? is.close();
?? is = null;
?? fc.close();
?? fc = null;
? } catch (IOException e) {
?? e.printStackTrace();
?? addStr("读文件出现异常" + e.toString());
? } catch (SecurityException e) {
?? e.printStackTrace();
?? addStr("读文件时出现权限错误");
? } finally {
?? if (is != null) {
??? try {
???? is.close();
??? } catch (IOException e) {
???? e.printStackTrace();
??? }
??? is = null;
?? }
?? if (fc != null) {
??? try {
???? fc.close();
??? } catch (IOException e) {
???? e.printStackTrace();
??? }
??? fc = null;
?? }
? }
}
/**
? * 清空信息
? *
? */
private void cls() {
? sb.delete(0, sb.length());
? form.deleteAll();
? // form.append(si);
? form.append(tf);
? form.append(info);
}
public void commandAction(Command c, Displayable arg1) {
? if (c == write) {// 读文件
?? new Thread() {
??? public void run() {
???? cls();
???? write(tf.getString().getBytes());
??? }
?? }.start();
? } else if (c == read) {// 写文件
?? new Thread() {
??? public void run() {
???? cls();
???? read();
??? }
?? }.start();
? } else if (c == exit) {// 退出
?? destroyApp(true);
?? notifyDestroyed();
? }
}
}