Android利用MD5码判断字符串是不是相等

Android利用MD5码判断字符串是否相等

MainActivity如下:

package cc.testmd5;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import android.os.Bundle;
import android.app.Activity;
/**
 * Demo描述:
 * 利用MD5判断两个字符串是否相同
 * 
 * MD5:消息摘要算法(Message Digest Algorithm)
 * MD5是常用的加密算法,常用于校验信息完整或者两次消息是否一致
 * 
 * 备注说明:
 * 1 hexadecimal 十六进制
 * 2 注意方法:String java.lang.Integer.toHexString(int i)
 *   Converts the specified integer into its hexadecimal string representation.
 *   The returned string is a concatenation of characters from '0' to '9' and 'a' to 'f'.
 *   将整型转换为十六进制
 * 
 */
public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		String firstMD5=getMD5("NBA");
		String secondMD5=getMD5("NBA");
		System.out.println("firstMD5="+firstMD5+",firstMD5.length()="+firstMD5.length());
		System.out.println("secondMD5="+secondMD5+",secondMD5.length()="+secondMD5.length());
		
	}
	private String getMD5(String string) {
		try {
			// Create MD5 Hash
			MessageDigest messageDigest = MessageDigest.getInstance("MD5");
			messageDigest.update(string.getBytes());
			byte messageDigestByteArray[] = messageDigest.digest();
			if (messageDigestByteArray == null || messageDigestByteArray.length == 0) {
				return "";
			}

			// Create hexadecimal String
			StringBuffer hexadecimalStringBuffer = new StringBuffer();
			int length = messageDigestByteArray.length;
			for (int i = 0; i < length; i++){
				hexadecimalStringBuffer.append(Integer.toHexString(0xFF & messageDigestByteArray[i]));
				}
			return hexadecimalStringBuffer.toString();

		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		return "";
	}
	

}

 

main.xml如下:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
   >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="测试Android的MD5码"
        android:layout_centerInParent="true"
    />

</RelativeLayout>