直接上程式碼：

將OpenSSL整個目錄複製到C盤根目錄即可

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Demo {
	/**
	 * @author LB win系統下 java 呼叫OpenSSL
	 */
	public static String CertName = "CA";

	/** 這幾個value為一些證書資訊，不懂的自行百度 */
	public static String Cvalue = "CC";// 長度限制，兩個字母
	public static String Svalue = "Svalue";
	public static String Lvalue = "Svalue";
	public static String Ovalue = "Ovalue";
	public static String OUvalue = "OUvalue";
	public static String CNvalue = "CNvalue";
	/** 這幾個value為一些證書資訊，不懂的自行百度 */

	public static String pw = "password";// 密碼
	public static int yxq = 3650;// 有效期

	public static void main(String[] args) {
		try {
			Runtime runtime = Runtime.getRuntime();
			// 開啟openSSL
			String cmd0 = "c:/OpenSSL/openssl.exe ";
			// 執行命令
			String cmd1 = "genrsa -out c:/cert/" + CertName + "-key.pem 1024 ";
			String cmd2 = "req -new -out c:/cert/" + CertName + "-req.csr -key c:/cert/" + CertName
					+ "-key.pem -passin pass:" + pw + " -subj  /C=" + Cvalue + "/ST=" + Svalue + "/L=" + Lvalue + "/O="
					+ Ovalue + "/OU=" + OUvalue + "/CN=" + CNvalue;
			String cmd3 = "x509 -req -in c:/cert/" + CertName + "-req.csr -out c:/cert/" + CertName
					+ "-cert.pem -signkey c:/cert/" + CertName + "-key.pem -days " + yxq;
			String cmd4 = "pkcs12 -export -clcerts -in c:/cert/" + CertName + "-cert.pem -inkey c:/cert/" + CertName
					+ "-key.pem -out c:/cert/" + CertName + ".p12 -password  pass:" + pw;
			Process process;
			int pcode = 0;
			process = runtime.exec(cmd0 + cmd1);
			pcode = process.waitFor();
			// pcode=0 ,無錯誤，等於1說明有錯誤。
			if (pcode == 1) {
				throw new Exception(getErrorMessage(process));
			}

			process = runtime.exec(cmd0 + cmd2);
			pcode = process.waitFor();
			if (pcode == 1) {
				throw new Exception(getErrorMessage(process));
			}

			process = runtime.exec(cmd0 + cmd3);
			pcode = process.waitFor();
			if (pcode == 1) {
				throw new Exception(getErrorMessage(process));
			}

			process = runtime.exec(cmd0 + cmd4);
			pcode = process.waitFor();
			if (pcode == 1) {
				throw new Exception(getErrorMessage(process));
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	// 得到控制檯輸出的錯誤資訊
	private static String getErrorMessage(Process process) {
		String errMeaage = null;
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(process.getErrorStream()));
			String line = null;
			StringBuilder sb = new StringBuilder();
			while ((line = br.readLine()) != null) {
				sb.append(line + "\n");
			}
			errMeaage = sb.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return errMeaage;
	}
}