System.out.println( " 输出证书信息:\n " + c.toString());
    System.out.println( " 版本号: " + t.getVersion());
    System.out.println( " 序列号: " + t.getSerialNumber().toString( 16 ));
    System.out.println( " 主体名： " + t.getSubjectDN());
    System.out.println( " 签发者： " + t.getIssuerDN());
    System.out.println( " 有效期： " + t.getNotBefore());
    System.out.println( " 签名算法： " + t.getSigAlgName());
     byte  [] sig = t.getSignature(); // 签名值  
     PublicKey pk = t.getPublicKey();
     byte  [] pkenc = pk.getEncoded();  
    System.out.println( " 公钥 " );
     for ( int  i = 0 ;i < pkenc.length;i ++ )System.out.print(pkenc[i] + " , " );

FileOutputStream output=new FileOutputStream("another");
    ks.store(output,storepass.toCharArray())将keystore对象内容写入新文件

FileInputStream in = new  FileInputStream( " .keystore " );
    KeyStore ks = KeyStore.getInstance( " JKS " );
    ks.load(in,storepass.toCharArray());
    ks.containsAlias( " sage " );检验条目是否在密钥库中，存在返回true
    ks.deleteEntry( " sage " );删除别名对应的条目
    FileOutputStream output = new  FileOutputStream( " .keystore " );
    ks.store(output,storepass.toCharArray())将keystore对象内容写入文件,条目删除成功

byte [] encod1 = c1.getEncoded();    提取CA证书的编码
    X509CertImpl cimp1 = new  X509CertImpl(encod1);  用该编码创建X509CertImpl类型对象
    X509CertInfo cinfo1 = (X509CertInfo)cimp1.get(X509CertImpl.NAME + " . " + X509CertImpl.INFO);  获取X509CertInfo对象
    X500Name issuer = (X500Name)cinfo1.get(X509CertInfo.SUBJECT + " . " + CertificateIssuerName.DN_NAME); 获取X509Name类型的签发者信息

    （4）获取待签发的证书   

CertificateFactory cf = CertificateFactory.getInstance( " X.509 " );
    FileInputStream in2 = new  FileInputStream( " user.csr " );
    java.security.cert.Certificate c2 = cf.generateCertificate(in);

byte  [] encod2 = c2.getEncoded();
    X509CertImpl cimp2 = new  X509CertImpl(encod2);  用该编码创建X509CertImpl类型对象
    X509CertInfo cinfo2 = (X509CertInfo)cimp2.get(X509CertImpl.NAME + " . " + X509CertImpl.INFO);  获取X509CertInfo对象

Date begindate = new  Date(); 获取当前时间
    Date enddate = new  Date(begindate.getTime() + 3000 * 24 * 60 * 60 * 1000L ); 有效期为3000天
    CertificateValidity cv = new  CertificateValidity(begindate,enddate); 创建对象
    cinfo2.set(X509CertInfo.VALIDITY,cv);  设置有效期

int  sn = ( int )(begindate.getTime() / 1000 );    以当前时间为序列号
    CertificateSerialNumber csn = new  CertificateSerialNumber(sn);
    cinfo2.set(X509CertInfo.SERIAL_NUMBER,csn);

    （8）设置新证书签发者  

cinfo2.set(X509CertInfo.ISSUER+"."+CertificateIssuerName.DN_NAME,issuer);应用第三步的结果

AlgorithmId algorithm=new AlgorithmId(AlgorithmId.md5WithRSAEncryption_oid);
    cinfo2.set(CertificateAlgorithmId.NAME+"."+CertificateAlgorithmId.ALGORITHM,algorithm);

X509CertImpl newcert=new X509CertImpl(cinfo2);
    newcert.sign(caprk,"MD5WithRSA"); 使用CA私钥对其签名

ks.setCertificateEntry( " lf_signed " ,newcert);
    FileOutputStream out = new  FileOutputStream( " newstore " );
    ks.store(out, " newpass " .toCharArray());  这里是写入了新的密钥库，也可以使用第七条来增加条目

十：数字证书的检验

CertificateFactory cf = CertificateFactory.getInstance( " X.509 " );
    FileInputStream in1 = new  FileInputStream( " aa.crt " );
  java.security.cert.Certificate  c1 = cf.generateCertificate(in1);
 X509Certificate t = (X509Certificate)c1;
  in2.close();

Date TimeNow=new Date();

try {
    t.checkValidity(TimeNow);
           System.out.println( " OK " );
 } catch (CertificateExpiredException e) {   // 过期 
     System.out.println( " Expired " );
    System.out.println(e.getMessage());
 } catch ((CertificateNotYetValidException e) {  // 尚未生效 
     System.out.println( " Too early " );
    System.out.println(e.getMessage());} 

CertificateFactory cf = CertificateFactory.getInstance( " X.509 " );
 FileInputStream in2 = new  FileInputStream( " caroot.crt " );
 java.security.cert.Certificate  cac = cf.generateCertificate(in2);
 in2.close();

boolean  pass = false ;
          try {
      c1.verify(pbk);
             pass = true ;
         } catch (Exception e) {
             pass = false ;
             System.out.println(e);
  }  

/*
 ==================================
 查询
 $query = $this->db_query("SELECT * FROM table");
 ==================================
*/
 
//result() 返回对象数组
$data = $query->result();
 
//result_array() 返回数据 
$data = $query->result_array();
 
//row() 只返回一行对象数组
$data = $query->row();
 
//num_rows() 返回查询结果行数
$data = $query->num_rows();
 
//num_fields() 返回查询请求的字段个数
$data = $query->num_fields();
 
//row_array() 只返回一行数组
$data = $query->row_array();
 
//free_result() 释放当前查询所占用的内存并删除关联资源标识
$data = $query->free_result();
 
/*
 ==================================
 插入操作
 ==================================
*/
 
//上次插入操作生成的ID
echo $this->db->insert_id();
 
//写入和更新操作被影响的行数
echo $this->db->affected_rows();
 
//返回指定表的总行数
echo $this->db->count_all(''table_name'');
 
//输出当前的数据库版本号
echo $this->db->version();
 
//输出当前的数据库平台
echo $this->db->platform();
 
//返回最后运行的查询语句
echo $this->db->last_query();
 
//插入数据，被插入的数据会被自动转换和过滤，例如：
//$data = array(''name'' => $name, ''email'' => $email, ''url'' => $url);
$this->db->insert_string(''table_name'', $data);
 
/*
 ==================================
 更新操作
 ==================================
*/
 
//更新数据，被更新的数据会被自动转换和过滤，例如：
//$data = array(''name'' => $name, ''email'' => $email, ''url'' => $url);
//$where = "author_id = 1 AND status = ''active''";
$this->db->update_string(''table_name'', $data, $where);
 
/*
 ==================================
 选择数据
 ==================================
*/
 
//获取表的全部数据
$this->db->get(''table_name'');
 
//第二个参数为输出条数，第三个参数为开始位置
$this->db->get(''table_name'', 10, 20);
 
//获取数据，第一个参数为表名，第二个为获取条件，第三个为条数
$this->db->get_where(''table_name'', array(''id''=>$id), $offset);
 
//select方式获取数据
$this->db->select(''title, content, date'');
$data = $this->db->get(''table_name'');
 
//获取字段的最大值，第二个参数为别名，相当于max(age) AS nianling
$this->db->select_max(''age'');
$this->db->select_max(''age'', ''nianling'');
 
//获取字段的最小值
$this->db->select_min(''age'');
$this->db->select_min(''age'', ''nianling'');
 
//获取字段的和
$this->db->select_sum(''age'');
$this->db->select_sum(''age'', ''nianling'');
 
//自定义from表
$this->db->select(''title'', content, date'');
$this->db->from(''table_name'');
 
//查询条件 WHERE name = ''Joe'' AND title = ''boss'' AND status = ''active''
$this->db->where(''name'', $name);
$this->db->where(''title'', $title);
$this->db->where(''status'', $status);
 
//范围查询
$this->db->where_in(''item1'', ''item2'');
$this->db->where_not_in(''item1'', ''item2'');
 
//匹配，第三个参数为匹配模式 title LIKE ''%match%''
$this->db->like(''title'', ''match'', ''before/after/both'');
$this->db->not_like();
 
//分组 GROUP BY title, date
$this->db->group_by(''title'', ''date'');
 
//限制条数
$this->db->limit(0, 20);