java 如何加密

import java.security.Key;
import java.security.SecureRandom;
 
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
 
/**
 * DES是一种对称加密算法，所谓对称加密算法:加密和解密使用相同的秘钥的算法
 * @author llp
 *
 */
public class DESUtil {
private static final Logger logger = LoggerFactory.getLogger(DESUtil.class);
 
private static Key key;
//设置秘钥key
private static String KEY_STR="myKey";
private static String CHARSETNAME="UTF-8";
private static String ALGORITHM="DES";
static{
try{
//生成DES算法对象
KeyGenerator generator=KeyGenerator.getInstance(ALGORITHM);
//运用SHA1安全策略
SecureRandom secureRandom=SecureRandom.getInstance("SHA1PRNG");
//设置上密钥种子
secureRandom.setSeed(KEY_STR.getBytes());
//初始化基于SHA1的算法对象
generator.init(secureRandom);
//生成密钥对象
key=generator.generateKey();
generator=null;
}catch(Exception e){
throw new RuntimeException(e);
}
}
/**
* 获取加密的信息
* @param str
* @return
*/
public static String getEncryptString(String str){
//基于BASE64编码，接收byte[]并转换成String
BASE64Encoder base64Encoder=new BASE64Encoder();
try {
// 按UTF8编码
byte[] bytes = str.getBytes(CHARSETNAME);
// 获取加密对象
Cipher cipher = Cipher.getInstance(ALGORITHM);
// 初始化密码信息
cipher.init(Cipher.ENCRYPT_MODE, key);
// 加密
byte[] doFinal = cipher.doFinal(bytes);
// byte[]to encode好的String并返回
return base64Encoder.encode(doFinal);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* 获取解密之后的信息
* 
* @param str
* @return
*/
public static String getDecryptString(String str) {
// 基于BASE64编码，接收byte[]并转换成String
BASE64Decoder base64decoder = new BASE64Decoder();
try {
// 将字符串decode成byte[]
byte[] bytes = base64decoder.decodeBuffer(str);
// 获取解密对象
Cipher cipher = Cipher.getInstance(ALGORITHM);
// 初始化解密信息
cipher.init(Cipher.DECRYPT_MODE, key);
// 解密
byte[] doFinal = cipher.doFinal(bytes);
// 返回解密之后的信息
return new String(doFinal, CHARSETNAME);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public static void main(String[] args) {
//加密
logger.info(getEncryptString("root"));//WnplV/ietfQ=
logger.info(getEncryptString("123456"));//QAHlVoUc49w=
//解密
logger.info(getDecryptString(getEncryptString("root")));//root
logger.info(getDecryptString(getEncryptString("123456")));//123456
}
}

import java.security.MessageDigest;
/**
 * MD5加密
 * @author llp
 *
 */
public class MD5 {
 
/**
* 对传入的String进行MD5加密
* 
* @param s
* @return
*/
public static final String getMd5(String s) {
// 16进制数组
char hexDigits[] = { '5', '0', '5', '6', '2', '9', '6', '2', '5', 'q', 'b', 'l', 'e', 's', 's', 
'y' };
try {
char str[];
// 将传入的字符串转换成byte数组
byte strTemp[] = s.getBytes();
// 获取MD5加密对象
MessageDigest mdTemp = MessageDigest.getInstance("MD5");
// 传入需要加密的目标数组
mdTemp.update(strTemp);
// 获取加密后的数组
byte md[] = mdTemp.digest();
int j = md.length;
str = new char[j * 2];
int k = 0;
// 将数组做位移
for (int i = 0; i < j; i++) {
byte byte0 = md[i];
str[k++] = hexDigits[byte0 >>> 4 & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
}
// 转换成String并返回
return new String(str);
} catch (Exception e) {
return null;
}
}
 
public static void main(String[] args) {
System.out.println(MD5.getMd5("123456"));//s05bse6q2qlb9qblls96s592y55y556s
}
}