MD5加密Util

目录：

• (1)需要导入的包
• (2)MD5Util类
• (3)使用举例

(1)需要导入的包

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.3.2</version>
    </dependency>
    <dependency>
        <groupId>commons-codec</groupId>
        <artifactId>commons-codec</artifactId>
        <version>1.10</version>
    </dependency>

(2)MD5Util类

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;


public class MD5Util {

    /**
     * 字符串签名
     * @param text    需要签名的字符串
     * @param key     密钥
     * @param charset 编码格式
     * @return 签名结果
     */
    public static String sign(String text, String key, String charset) {
        //拼接key
        text = text + key;
        return DigestUtils.md5Hex(getContentBytes(text, charset));
    }

    /**
     * 根据参数map签名
     * @param map 有序map
     * @param key
     * @param charset
     * @return
     */
    public static String sign(TreeMap<String, Object> map, String key, String charset){
        Set<String> keySet = map.keySet();
        StringBuilder sb = new StringBuilder();
        for (String mapKey : keySet){
            String value = (String)map.get(key);
            sb.append(key).append("=").append(value).append("&");
        }
        return sign(sb.toString(), key, charset);
    }


    /**
     * 根据参数map签名
     * @param map hashMap
     * @param key
     * @param charset
     * @return
     */
    public static String sign1(Map<String, Object> map, String key, String charset){
        Set<String> keySet = map.keySet();
        StringBuilder sb = new StringBuilder();
        for (String mapKey : keySet){
            String value = (String)map.get(key);
            sb.append(key).append("=").append(value).append("&");
        }
        return sign(sb.toString(), key, charset);
    }

    /**
     * 根据参数map签名
     * @param map hashMap
     * @param key
     * @param charset
     * @return
     */
    public static String sign(Map<String, String> map, String key, String charset){
        Set<String> keySet = map.keySet();
        StringBuilder sb = new StringBuilder();
        for (String mapKey : keySet){
            String value = (String)map.get(key);
            sb.append(key).append("=").append(value).append("&");
        }
        return sign(sb.toString(), key, charset);
    }

    /**
     * 根据字符串获取byte[]
     * @param content
     * @param charset
     * @return
     */
    private static byte[] getContentBytes(String content, String charset){
        if (StringUtils.isEmpty(charset)) {
            return content.getBytes();
        }
        try {
            return content.getBytes(charset);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("转码过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);
        }
    }

    /**
     * 签名，不用加密码
     * @param origin
     * @param charsetname
     * @return
     */
    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
        } catch (Exception exception) {
        }
        return resultString;
    }
    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }
    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };


}

(3)使用举例

//加密

//要加密的数据map<String, String>
Map<String, String> data = new TreeMap<String, String>();
String key="key123";//加密key  
String sign = MD5Util.sign(data, key, "utf-8");

//要加密的数据map<String, Object>
Map<String, Object> result = new TreeMap<String, Object>();
String key="key123";//加密key  
String sign = MD5Util.sign1(data, key, "utf-8");

//不用密码的加密，加密一个String
String sign=MD5Util.MD5Encode(mchkey, "utf-8");