getInstance( String algorithm )
java.security.SecureRandom类的getInstance()方法用于返回实现指定的随机数生成器(RNG)算法的SecureRandom对象。
此方法从最喜欢的提供者开始遍历已注册的安全提供者列表。返回一个新的SecureRandom对象,该对象封装了支持指定算法的第一个Provider的SecureRandomSpi实现。
用法:
public static SecureRandom getInstance( String algorithm ) throws NoSuchAlgorithmException
参数:该方法以标准RNG算法为参数。
返回值:此方法返回新的SecureRandom对象。
异常:如果没有提供者支持指定算法的SecureRandomSpi实现,则此方法引发NoSuchAlgorithmException。
注意:
- 该程序将无法在在线IDE上运行。
- 每次Secure Random类将生成随机输出。
下面是说明getInstance()方法的示例:
示例1:
// Java program to demonstrate
// nextBytes() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void main(String[] argv)
{
try {
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (ProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Byte array before operation : [84, 97, 106, 109, 97, 104, 97, 108] Byte array after operation : [124, -66, -62, -5, -71, -4, 30, 16]
示例2:
// Java program to demonstrate
// getInstance() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void main(String[] argv)
{
try {
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
System.out.println("Trying to get the instance of TAJMAHAL");
SecureRandom sr = SecureRandom.getInstance("TAJMAHAL");
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (ProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Trying to get the instance of TAJMAHAL Exception thrown : java.security.NoSuchAlgorithmException: TAJMAHAL SecureRandom not available
getInstance(String algorithm, Provider provider)
java.security.SecureRandom类的getInstance()方法用于返回实现指定的随机数生成器(RNG)算法的SecureRandom对象。
返回一个封装了指定Provider对象中的SecureRandomSpi实现的新SecureRandom对象。请注意,指定的提供程序对象不必在提供程序列表中注册。
返回的SecureRandom对象尚未设定种子。要播种返回的对象,请调用setSeed方法。如果未调用setSeed,则对nextBytes的第一次调用将强制SecureRandom对象播种自身。如果先前调用过setSeed,则不会发生此self-seeding。
用法:
public static SecureRandom getInstance( String algorithm, Provider provider ) throws NoSuchAlgorithmException
参数:此方法将以下参数作为参数
- algorithm –RNG算法的名称。
- provider –提供者。
返回值:此方法返回新的SecureRandom对象。
异常:此方法引发以下异常
- NoSuchAlgorithmException –如果指定的Provider对象不提供指定算法的SecureRandomSpi实现。
- IllegalArgumentException –如果指定的提供者为null。
注意:
- 该程序将无法在在线IDE上运行。
- 每次Secure Random类将生成随机输出。
下面是说明getInstance()方法的示例:
示例1:
// Java program to demonstrate
// getInstance() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void main(String[] argv)
{
try {
// creating SecureRandom object
SecureRandom sr1 = new SecureRandom(new byte[] { 1, 2, 3, 4 });
// creating Provider object
Provider pd = sr1.getProvider();
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", pd);
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (ProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Byte array before operation : [84, 97, 106, 109, 97, 104, 97, 108] Byte array after operation : [109, 55, 116, -15, -83, 126, -128, 88]
注意:以下程序在在线IDE中产生以下异常
引发异常:java.security.ProviderException:初始化失败
示例2:
// Java program to demonstrate
// getInstance() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void main(String[] argv)
{
try {
// creating SecureRandom object
SecureRandom sr1 = new SecureRandom(new byte[] { 1, 2, 3, 4 });
// creating Provider object
Provider pd = sr1.getProvider();
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
System.out.println("Trying to getting the instance of TAJMAHAL ");
SecureRandom sr = SecureRandom.getInstance("TAJMAHAL", pd);
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (ProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Trying to getting the instance of TAJMAHAL Exception thrown : java.security.NoSuchAlgorithmException: no such algorithm: TAJMAHAL for provider SUN
getInstance(String algorithm, String provider)
java.security.SecureRandom类的getInstance()方法用于返回实现指定的随机数生成器(RNG)算法的SecureRandom对象。
返回一个封装了指定提供者的SecureRandomSpi实现的新SecureRandom对象。指定的提供者必须在安全提供者列表中注册。
用法:
public static SecureRandom getInstance( String algorithm, String provider ) throws NoSuchAlgorithmException, NoSuchProviderException
参数:此方法将以下参数作为参数
- algorithm – RNG算法的名称。有关标准RNG算法名称的信息,请参见Java密码体系结构标准算法名称文档中的SecureRandom部分。
- provider –提供者的名称。
返回值:此方法返回新的SecureRandom对象。
异常:此方法引发以下异常
- NoSuchAlgorithmException–如果指定提供者无法使用指定算法的SecureRandomSpi实现。
- NoSuchProviderException–如果指定的提供者未在安全提供者列表中注册。
- IllegalArgumentException–如果提供者名称为null或为空。
注意:
- 该程序将无法在在线IDE上运行。
- 每次Secure Random类将生成随机输出。
下面是说明getInstance()方法的示例:
示例1:
// Java program to demonstrate
// getInstance() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void
main(String[] argv)
throws NoSuchAlgorithmException,
NoSuchProviderException
{
try {
// creating SecureRandom object
SecureRandom sr1 = new SecureRandom(new byte[] { 1, 2, 3, 4 });
// creating Provider object
Provider pd = sr1.getProvider();
// getting provider name
// by using method getname()
String provider = pd.getName();
// getting algorithm name
// by using getAlgorithm() mathod
String algo = sr1.getAlgorithm();
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
SecureRandom sr = SecureRandom.getInstance(algo, provider);
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (ProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Byte array before operation : [84, 97, 106, 109, 97, 104, 97, 108] Byte array after operation : [-11, 81, 39, 67, -95, -51, 115, -18]
示例2:
// Java program to demonstrate
// getInstance() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void
main(String[] argv)
throws NoSuchAlgorithmException,
NoSuchProviderException
{
try {
// creating SecureRandom object
SecureRandom sr1 = new SecureRandom(new byte[] { 1, 2, 3, 4 });
// creating Provider object
Provider pd = sr1.getProvider();
// getting provider name
// by using method getname()
String provider = pd.getName();
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
System.out.println("Trying to take TAJMAHAL as a algorithm");
SecureRandom sr = SecureRandom.getInstance("TAJMAHAL", provider);
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (ProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Trying to take TAJMAHAL as a algorithm Exception thrown : java.security.NoSuchAlgorithmException: no such algorithm: TAJMAHAL for provider SUN
示例3:
// Java program to demonstrate
// getInstance() method
import java.security.*;
import java.util.*;
public class GFG1 {
public static void
main(String[] argv)
throws NoSuchAlgorithmException,
NoSuchProviderException
{
try {
// creating SecureRandom object
SecureRandom sr1 = new SecureRandom(new byte[] { 1, 2, 3, 4 });
// getting algorithm name
// by using getAlgorithm() mathod
String algo = sr1.getAlgorithm();
// creating the object of SecureRandom and getting instance
// By usng getInstance() method
System.out.println("Trying to taking MOON as a provider");
SecureRandom sr = SecureRandom.getInstance(algo, "MOON");
// Declaring the string variable
String str = "Tajmahal";
// Declaring the byte Array
// converting string into byte
byte[] b = str.getBytes();
// printing the byte array
System.out.println("Byte array before operation : "
+ Arrays.toString(b));
// generating user-specified number of random bytes
// using nextBytes() method
sr.nextBytes(b);
// printing the new byte array
System.out.println("Byte array after operation : "
+ Arrays.toString(b));
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
}
catch (NoSuchProviderException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Trying to taking MOON as a provider Exception thrown : java.security.NoSuchProviderException: no such provider: MOON
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注:本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 SecureRandom getInstance() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。