MD5加密的使用

*MD5加密只能单向加密，不能解密。每次都是32位的结果*

第一种：MD5Utils 推荐

public class MD5Utils {

public static String getMD5_16bits(String str) {
return getMD5_32bits(str).substring(8, 24);
}

public static String getMD5_32bits(String str) {
if(str == null || str.equals("")){
throw new RuntimeException("md5加密内容不能为空");
}
MessageDigest md=null;
try {
md = MessageDigest.getInstance("MD5");
byte[] md5Bytes = md.digest(str.getBytes());
StringBuffer hexValue = new StringBuffer();
for (int i = 0; i < md5Bytes.length; i++) {
int val = ((int) md5Bytes[i]) & 0xff;
if (val < 16)
hexValue.append("0");
hexValue.append(Integer.toHexString(val));
}
str = hexValue.toString();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return str;
}

}

第二种： MD5和SHA1加密工具方法

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;

/**
* 数据加密工具类型，主要提供了MD5和SHA1加密工具方法
*
* @author Lu Jianliang
*
*/
public class EncryptUtil {
public static final String KEY_SHA = "SHA";

public static final String KEY_MD5 = "MD5";

public static final String KEY_SHA1 = "SHA-1";

private static final String KEY_SHA256 = "SHA-256";

private static final String KEY_SHA512 = "SHA-512";

/**
* BASE64解码
*
* @param key
* -需要解码的密码字符串
* @return
* @throws Exception
*/
public static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}

/**
* BASE64编码
*
* @param key
* -需要编码的字节数组
* @return
* @throws Exception
*/
public static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}

/**
* MD5加密
*
* @param data
* - 需要加密的字节数组
* @return
* @throws Exception
*/
public static byte[] encryptMD5(byte[] data) throws Exception {

MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);
md5.update(data);

return md5.digest();

}

/**
* SHA加密
*
* @param data
* -需要加密的字节数组
* @return
* @throws Exception
*/
public static byte[] encryptSHA(String shaType,byte[] data) throws Exception {

MessageDigest sha = MessageDigest.getInstance(shaType);
sha.update(data);

return sha.digest();

}

/**
* SHA1加密
*
* @param data
* -需要加密的字节数组
* @return
* @throws Exception
*/
public static byte[] encryptSHA1(byte[] data) throws Exception {

return encryptSHA(KEY_SHA1, data);

}

/**
* SHA256加密
*
* @param data
* -需要加密的字节数组
* @return
* @throws Exception
*/
public static byte[] encryptSHA256(byte[] data) throws Exception {

return encryptSHA(KEY_SHA256, data);

}

/**
* SHA512加密
*
* @param data
* -需要加密的字节数组
* @return
* @throws Exception
*/
public static byte[] encryptSHA512(byte[] data) throws Exception {

return encryptSHA(KEY_SHA512, data);

}

/**
* MD5加密
*
* @param content
* -待加密明文字符串
* @param charset
* -待加密明文字符串采用的字符编码集
* @return -返回MD5加密后的字符串
*/
public static String encryptMD5(String content, String charset) {
try {
byte[] b = encryptMD5(content.getBytes(charset));
StringBuffer buffer = new StringBuffer();

for (int i = 0; i < b.length; i++) {
String shaHex = Integer.toHexString(b[i] & 0xFF);
if (shaHex.length() < 2) {
buffer.append(0);
}
buffer.append(shaHex);
}
return buffer.toString();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return "";

}

/**
* MD5加密算法，该方法采用UTF-8编码集将明文进行转换，如果明文字符串为其他字符编码，<br>
* 请采用<code>encryptMD5(String content,String charset)</code>方法
*
* @param content
* -待加密明文字符串
* @return -返回加密后密文字符串
*/
public static String encryptMD5(String content) {
return encryptMD5(content, "UTF-8");
}

/**
* SHA加密算法
*
* @param content -待加密明文
* @param charset -明文所采用字符编码集
* @return
*/
public static String encryptSHA(String shaType,String content, String charset) {
try {
byte[] b = encryptSHA(shaType,content.getBytes(charset));
StringBuffer buffer = new StringBuffer();
// 字节数组转换为 十六进制 数
for (int i = 0; i < b.length; i++) {
String shaHex = Integer.toHexString(b[i] & 0xFF);
if (shaHex.length() < 2) {
buffer.append(0);
}
buffer.append(shaHex);
}
return buffer.toString();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return "";
}

/**
* SHA加密算法
* @param content -待加密明文字符串
* @return
*/
public static String encryptSHA(String shaType,String content){
return encryptSHA(shaType,content,"UTF-8");
}

/**
* SHA1加密算法
* @param content -待加密明文字符串
* @param charset -明文所采用字符编码集
* @return
*/
public static String encryptSHA1(String content,String charset){

return encryptSHA(KEY_SHA1, content,charset);
}


/**
* SHA1加密算法
* @param content -待加密明文字符串
* @return
*/
public static String encryptSHA1(String content){
return encryptSHA1(content,"UTF-8");
}

/**
* SHA256加密算法
* @param content -待加密明文字符串
* @param charset -明文所采用字符编码集
* @return
*/
public static String encryptSHA256(String content,String charset){

return encryptSHA(KEY_SHA256, content,charset);
}


/**
* SHA256加密算法
* @param content -待加密明文字符串
* @return
*/
public static String encryptSHA256(String content){
return encryptSHA256(content,"UTF-8");
}

/**
* SHA512加密算法
* @param content -待加密明文字符串
* @param charset -明文所采用字符编码集
* @return
*/
public static String encryptSHA512(String content,String charset){

return encryptSHA(KEY_SHA512, content,charset);
}


/**
* SHA512加密算法
* @param content -待加密明文字符串
* @return
*/
public static String encryptSHA512(String content){
return encryptSHA512(content,"UTF-8");
}

}