如何在Java中解密sha1加密的String

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.nio.charset.StandardCharsets;

public class SHA1Example {
    public static void main(String[] args) {
        String input = "Hello, world!";
        String expectedSHA1Hash = "65a8e27d8879283831b664bd8b7f0ad4";

        try {
            // 生成SHA-1哈希值
            MessageDigest md = MessageDigest.getInstance("SHA-1");
            byte[] inputBytes = input.getBytes(StandardCharsets.UTF_8);
            byte[] hashBytes = md.digest(inputBytes);

            // 将字节数组转换为十六进制字符串
            StringBuilder sb = new StringBuilder();
            for (byte b : hashBytes) {
                sb.append(String.format("%02x", b));
            }
            String actualSHA1Hash = sb.toString();

            // 检查哈希值是否匹配
            if (actualSHA1Hash.equalsIgnoreCase(expectedSHA1Hash)) {
                System.out.println("哈希值匹配！");
            } else {
                System.out.println("哈希值不匹配！");
            }
        } catch (NoSuchAlgorithmException e) {
            System.err.println("SHA-1算法不可用：" + e.getMessage());
        }
    }
}