来源: 互联网  发布时间: 2014-02-18

将程序安装到SD卡
Android 2.2系统的一大改进就是通过Move to SD Card功能让用户可以安装程序到SD卡，不用担心手机内存不足的问题。但是最近很多安装Nexus One更新的用户都反映Move to SD Card功能不能使用，有人甚至担心自己安 装的Android 2.2升级是阉割版。

其实问题既不是出在Android 2.2系统也不是用户安装的Android 2.2更新，而是出在开发者那里。开发者如果想让自己的程序可以安装在运行Android 2.2系统收集的SD里，必须在程序Manifest文件里添上下面这两行内容：

xmlns:android=”http://schemas.android.com/apk/res/android”
android:installLocation=”auto”
… >
如果每个程序都需要进行上面的修改，可以想见接下来Android Market里的程序将有一波规模空前的升级热潮，不过我觉得还有一个可能性就是Google对Android 2.2发布一个小的更新，让所有程序自动添加这个功能，在系统层面解决，不要麻烦开发者和用户了 。

    

    来源: 互联网  发布时间: 2014-02-18

一个很好的加密解密字符串
package net.sf.andhsli.hotspotlogin;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
* Usage:
* <pre>
* String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)
* ...
* String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)
* </pre>
* @author ferenc.hechler
*/
public class SimpleCrypto {

public static String encrypt(String seed, String cleartext) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes());
byte[] result = encrypt(rawKey, cleartext.getBytes());
return toHex(result);
}

public static String decrypt(String seed, String encrypted) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes());
byte[] enc = toByte(encrypted);
byte[] result = decrypt(rawKey, enc);
return new String(result);
}

private static byte[] getRawKey(byte[] seed) throws Exception {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(seed);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
return raw;
}


private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(clear);
return encrypted;
}

private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encrypted);
return decrypted;
}

public static String toHex(String txt) {
return toHex(txt.getBytes());
}
public static String fromHex(String hex) {
return new String(toByte(hex));
}

public static byte[] toByte(String hexString) {
int len = hexString.length()/2;
byte[] result = new byte[len];
for (int i = 0; i < len; i++)
result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
return result;
}

public static String toHex(byte[] buf) {
if (buf == null)
return "";
StringBuffer result = new StringBuffer(2*buf.length);
for (int i = 0; i < buf.length; i++) {
appendHex(result, buf[i]);
}
return result.toString();
}
private final static String HEX = "0123456789ABCDEF";
private static void appendHex(StringBuffer sb, byte b) {
sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
}

}

    

    来源: 互联网  发布时间: 2014-02-18

Java判断中文及中文字符转unicode

1、java中判断字符是否为中文   public String chinaToUnicode(String str){        String result="";        for (int i = 0; i < str.length(); i++){             int chr1 = (char) str.charAt(i);             if(chr1>=19968&&chr1<=171941){//汉字范围 \u4e00-\u9fa5 (中文)                 result+="\\u" + Integer.toHexString(chr1);             }else{                 result+=str.charAt(i);             }        }