漯河河南网站建设,雇主品牌建设,网络空间购买,中关村手机报价大全官网java.security.MessageDigest
MessageDigest的含义
message含义是:消息,信息
digest的含义是 digest 必应词典 n.摘要#xff1b;文摘#xff1b;概要#xff1b;汇编 v.消化#xff1b;领会#xff1b;领悟#xff1b;理解 海词 n. 摘要 vt. 消化#xff1b;理解 vi…java.security.MessageDigest
MessageDigest的含义
message含义是:消息,信息
digest的含义是 digest 必应词典 n.摘要文摘概要汇编 v.消化领会领悟理解 海词 n. 摘要 vt. 消化理解 vi. 消化 金山词霸 v. 消化; 理解 n. 摘要; 文摘 有道 v. 理解领悟消化 n. 文摘摘要分解物提炼物 所以 MessageDigest 可以理解为 消息消化
额,不是.
应该是 信息摘要 或 数据摘要
它能将很大的信息(数据)(文件)通过某种算法(algorithm),简化为简短的内容, 用于判断大数据是否相同.
动态获取 MessageDigest 所支持的算法名称
java.security.Security.getAlgorithms(MessageDigest); 可获得算法名称的SetString集合 , 参数为MessageDigest,不区分大小写
java.util.SetString messageDigest_AlgorithmNames_Set java.security.Security.getAlgorithms(MessageDigest); //不区分大小写java.util.SetString messageDigest_AlgorithmNames_Set java.security.Security.getAlgorithms(messagedigest); //不区分大小写示例
public class Try动态获取MessageDigest支持的算法名称列表 {static Integer numA 1;static public void main(String...arguments)throws Exception{java.util.SetString messageDigest_AlgorithmNames_Set java.security.Security.getAlgorithms(messagedigest);
// java.util.SetString messageDigest_AlgorithmNames_Set java.security.Security.getAlgorithms(MessageDigest);System.out.println(MessageDigest的算法种类个数为: messageDigest_AlgorithmNames_Set.size() , 分别为);messageDigest_AlgorithmNames_Set.forEach(算法名称-{System.out.println(numA.\t\t算法名称);}); }
}控制台输出 (JDK17)
MessageDigest的算法种类个数为: 13 , 分别为
1. SHA3-512
2. SHA-1
3. SHA-384
4. SHA3-384
5. SHA-224
6. SHA-512/256
7. SHA-256
8. MD2
9. SHA-512/224
10. SHA3-256
11. SHA-512
12. MD5
13. SHA3-224获取 MessageDigest 的实例
MessageDigest 的实例由 MessageDigest.getInstance(x) 方法获得; 一个MessageDigest实例只能指定一种算法;
MessageDigest md_SHA3512 MessageDigest.getInstance(SHA3-512);
MessageDigest md_SHA1 MessageDigest.getInstance(SHA-1);
MessageDigest md_SHA384 MessageDigest.getInstance(SHA-384);
MessageDigest md_SHA3384 MessageDigest.getInstance(SHA3-384);
MessageDigest md_SHA224 MessageDigest.getInstance(SHA-224);
MessageDigest md_SHA512256 MessageDigest.getInstance(SHA-512/256);
MessageDigest md_SHA256 MessageDigest.getInstance(SHA-256);
MessageDigest md_MD2 MessageDigest.getInstance(MD2);
MessageDigest md_SHA512224 MessageDigest.getInstance(SHA-512/224);
MessageDigest md_SHA3256 MessageDigest.getInstance(SHA3-256);
MessageDigest md_SHA512 MessageDigest.getInstance(SHA-512);
MessageDigest md_MD5 MessageDigest.getInstance(MD5);
MessageDigest md_SHA3224 MessageDigest.getInstance(SHA3-224);将byte数组计算为Hash
MessageDigest 通过 update 和 digest 方法, 将一个或多个byte[]数组计算为Hash摘要
digest(byte[] input) 是一步到位的方法, 直接计算出input数组的Hash, 但是有一个问题, 数组索引是int, intInteger.MAX; 大概2G多, 所以对很大的文件无能为力.
digest(byte[] input) 的源码
public byte[] digest(byte[] input) {update(input);return digest();}可看出也是分为两步, 第一步是update(input), 将数组放入MessageDigest, 让后再digest()计算. 实际上update方法可以多次调用, 所以可以将大文件用缓存数组buffer拆分成多段用update放入 而且update有个现成的重载:update(byte[] input, int offset, int len)
示例 FileInputStream is new FileInputStream(pathStr);MessageDigest digest MessageDigest.getInstance(SHA-256);byte[] bf new byte[10240];int numRead;do {numRead is.read(bf);if (numRead 0) {digest.update(bf, 0, numRead);}} while (numRead ! -1);is.close();byte[] resultByteArray digest.digest();得到的结果还是byte数组, 可将其转为16进制
将digest的结果数组转为16进制
假设已得到结果: resultByteArray
将其转为16进制的办法 public static String bytesToHex(byte[] bytes) {StringBuilder sb new StringBuilder();for (int i 0; i bytes.length; i) {sb.append(String.format(%02x, bytes[i]));}return sb.toString();}String resultHex bytesToHex(resultByteArray)小写
public static String hexLowerCaseFromByteArray(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)4)).append(simple.charAt(b2828));}return sb.toString();}String resultHex bytesToHex(resultByteArray)大写 public static String hexUpperCaseFromByteArray(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)4)).append(simple.charAt(b2828));}return sb.toString();}String resultHex bytesToHex(resultByteArray)public static String hexLowerCaseFromByteArray2(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)/16)).append(simple.charAt((b0xff)%16));}return sb.toString();}public static String hexUpperCaseFromByteArray2(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)/16)).append(simple.charAt((b0xff)%16));}return sb.toString();}public static String hexLowerCaseFromByteArray3(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b255)/16)).append(simple.charAt((b255)%16));}return sb.toString();}public static String hexUpperCaseFromByteArray3(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b255)/16)).append(simple.charAt((b255)%16));}return sb.toString();} public static String hexLowerCaseFromByteArray4(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {int ib0?b:b256;sb.append(simple.charAt(i/16)).append(simple.charAt(i%16));}return sb.toString();}public static String hexUpperCaseFromByteArray4(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {int ib0?b:b256;sb.append(simple.charAt(i/16)).append(simple.charAt(i%16));}return sb.toString();} public static String hexLowerCaseFromByteArray5(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt(Byte.toUnsignedInt(b)/16)).append(simple.charAt(Byte.toUnsignedInt(b)%16));}return sb.toString();}public static String hexUpperCaseFromByteArray5(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt(Byte.toUnsignedInt(b)/16)).append(simple.charAt(Byte.toUnsignedInt(b)%16));}return sb.toString();}测试
package 将byte数组转为16进制字符串的方法;import java.awt.FileDialog;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileInputStream;
import java.security.MessageDigest;import javax.swing.JFrame;public class ByteArrayToHexString {public static String hexLowerCaseFromByteArray(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)4)).append(simple.charAt(b2828));}return sb.toString();}public static String hexUpperCaseFromByteArray(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)4)).append(simple.charAt(b2828));}return sb.toString();}public static String hexLowerCaseFromByteArray2(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)/16)).append(simple.charAt((b0xff)%16));}return sb.toString();}public static String hexUpperCaseFromByteArray2(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b0xff)/16)).append(simple.charAt((b0xff)%16));}return sb.toString();}public static String hexLowerCaseFromByteArray3(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b255)/16)).append(simple.charAt((b255)%16));}return sb.toString();}public static String hexUpperCaseFromByteArray3(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt((b255)/16)).append(simple.charAt((b255)%16));}return sb.toString();}public static String hexLowerCaseFromByteArray4(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {int ib0?b:b256;sb.append(simple.charAt(i/16)).append(simple.charAt(i%16));}return sb.toString();}public static String hexUpperCaseFromByteArray4(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {int ib0?b:b256;sb.append(simple.charAt(i/16)).append(simple.charAt(i%16));}return sb.toString();}public static String hexLowerCaseFromByteArray5(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789abcdef;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt(Byte.toUnsignedInt(b)/16)).append(simple.charAt(Byte.toUnsignedInt(b)%16));}return sb.toString();}public static String hexUpperCaseFromByteArray5(byte[] byteArray) {if(byteArraynull)return null;String simple 0123456789ABCDEF;StringBuilder sb new StringBuilder(byteArray.length*2);for(byte b : byteArray) {sb.append(simple.charAt(Byte.toUnsignedInt(b)/16)).append(simple.charAt(Byte.toUnsignedInt(b)%16));}return sb.toString();}public static String hexLowerCaseFromByteArray6(byte[] byteArray) {if(byteArraynull)return null;StringBuilder sb new StringBuilder();for (int i 0; i byteArray.length; i) {sb.append(String.format(%02x, byteArray[i]));}return sb.toString();}public static void main(String...arguments)throws Exception{JFrame frame new JFrame(Thread.currentThread().getStackTrace()[1].getClassName());frame.addWindowListener(new WindowAdapter() {Override public void windowClosing(WindowEvent ev) {System.exit(0);}});FileDialog fDialog new FileDialog(frame);fDialog.setVisible(true);if(fDialog.getFile()!null) {String pathFile fDialog.getDirectory()fDialog.getFile();FileInputStream is new FileInputStream(pathFile);MessageDigest digest MessageDigest.getInstance(SHA-256);byte[] bf new byte[10240];int numRead;do {numRead is.read(bf);if (numRead 0) {digest.update(bf, 0, numRead);}} while (numRead ! -1);is.close();byte[] resultByteArray digest.digest();String result;result hexLowerCaseFromByteArray(resultByteArray); System.out.println(result);result hexUpperCaseFromByteArray(resultByteArray); System.out.println(result);result hexLowerCaseFromByteArray2(resultByteArray); System.out.println(result);result hexUpperCaseFromByteArray2(resultByteArray); System.out.println(result);result hexLowerCaseFromByteArray3(resultByteArray); System.out.println(result);result hexUpperCaseFromByteArray3(resultByteArray); System.out.println(result);result hexLowerCaseFromByteArray4(resultByteArray); System.out.println(result);result hexUpperCaseFromByteArray4(resultByteArray); System.out.println(result);result hexLowerCaseFromByteArray5(resultByteArray); System.out.println(result);result hexUpperCaseFromByteArray5(resultByteArray); System.out.println(result);result hexLowerCaseFromByteArray6(resultByteArray); System.out.println(result);}System.exit(0);}} 一些应用例子
例1 import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileInputStream;
import java.security.MessageDigest;
import java.util.*;import javax.swing.*;//import javax.swing.JButton;public class SHA_MD_MessageDigest_230528 extends Frame{/*** */private static final long serialVersionUID 5242216018207119189L;static void pln(Object o) {System.out.println(o);}public final SHA_MD_MessageDigest_230528 I;public final TextArea resultLowercaseShow new TextArea(这里展示小写结果);public final TextArea resultUppercaseShow new TextArea(这里展示大写结果);public final HashMapString, MessageDigest DigestGroup new HashMap();public final LinkedHashMapString, Panel ButtonForComputedGroup new LinkedHashMap();{SetString set java.security.Security.getAlgorithms(MessageDigest); //获得支持的格式ArrayListString nmAl new ArrayList(set);nmAl.sort((o1,o2)-o1.compareTo(o2));try {for(String nm : set) {DigestGroup.put(nm, MessageDigest.getInstance(nm));}nmAl.forEach(nm-{ButtonForComputedGroup.put(nm, new Btn(nm));});}catch(Exception ex) {ex.printStackTrace();}}//constructor 构造方法在此public SHA_MD_MessageDigest_230528() {Ithis;setTitle(文件校验, 点击按钮选择文件 );addWindowListener(new WindowAdapter() {Overridepublic void windowClosing(WindowEvent e) {I.dispose();System.exit(0);}});setLayout(new GridLayout(3, 0, 1, 3));Panel up new Panel(); add(up); up.setBackground(Color.DARK_GRAY);Panel panel010 new Panel(); add(panel010);
// Panel panel020 new Panel(); add(panel020);JPanel panel020 new JPanel(); add(panel020);ButtonForComputedGroup.forEach((lb,btn)-{up.add(btn);});panel010.setLayout(new BorderLayout(200,200)); panel010.add(resultLowercaseShow);System.out.println(panel020.getLayout());panel020.setLayout(new BorderLayout());panel020.add(resultUppercaseShow);setBounds(258, 235, 1600, 666);setVisible(true);
// show();}public static void main(String ags[]) {new SHA_MD_MessageDigest_230528();}void computed(String nm) {pln(nm);String lowercaseMapping 0123456789abcdef , uppercaseMapping lowercaseMapping.toUpperCase();FileDialog fileDialog new FileDialog(this, 选择要生成Hash的文件, FileDialog.LOAD);fileDialog.setVisible(true);String directoryStr fileDialog.getDirectory() , fileStr fileDialog.getFile();if(directoryStr!null fileStr!null) {try {String pathStr directoryStrfileStr;resultLowercaseShow.setText(正在计算 pathStr 的nm值);FileInputStream is new FileInputStream(pathStr);MessageDigest digest DigestGroup.get(nm);byte[] bf new byte[10240];int numRead;do {numRead is.read(bf);if (numRead 0) {digest.update(bf, 0, numRead);}} while (numRead ! -1);is.close();bf digest.digest();StringBuilder sb new StringBuilder(bf.length*2);for(byte b : bf) {int idx1(b0xff)4 , idx2b2828;pln(idx1idx1 idx2idx2);sb.append(lowercaseMapping.charAt(idx1)).append(lowercaseMapping.charAt(idx2));}String hexLower sb.toString();resultLowercaseShow.setText(hexLower);sb new StringBuilder(bf.length*2);for(byte b : bf) {int idx1(b0xff)4 , idx2b2828;pln(idx1idx1 idx2idx2);sb.append(uppercaseMapping.charAt(idx1)).append(uppercaseMapping.charAt(idx2));}String hexUpper sb.toString();resultUppercaseShow.setText(hexUpper);}catch(Throwable ex) {ex.printStackTrace(); resultLowercaseShow.setText(ex.toString()); }}}class Btn extends Panel{/*** 镶嵌在Panel中的Button*/private static final long serialVersionUID -3494086542207800072L;public final Button btn;Btn(String label){super();this.setBackground(Color.blue);
// setLayout(new BorderLayout());setLayout(null);setSize(210,60);btn new Button(label);switch (label) {caseMD5,SHA-256: btn.setForeground(Color.BLUE); break;caseSHA-512: btn.setForeground(Color.WHITE);btn.setBackground(new Color(0,168,255)); break;}btn.setBounds(5, 5, 200, 50);setFont(new Font(宋体, Font.CENTER_BASELINE, 25));btn.addActionListener(ev-{computed(btn.getActionCommand());});add(btn);}}}
