1、进入dos命令行，进入目录C:\Program Files (x86)\Java\jre6\lib\security，

 导入命令：

       keytool -import -keystore "C:\Program Files (x86)\Java\jre6\lib\security\cacerts"  -storepass changeit

      -keypass changeit -alias emailcert -file test.cer

       所有者:CN=yu, OU=chinaabc, O=chinaabc, L=beijing, ST=beijing, C=cn
       签发人:CN=yu, OU=chinaabc, O=chinaabc, L=beijing, ST=beijing, C=cn
       序列号:517754e3
       有效期: Wed Apr 24 11:43:31 CST 2013 至Tue Jul 23 11:43:31 CST 2013
       证书指纹:
               MD5:26:E3:EB:82:5C:35:A5:D3:03:EF:10:FA:D0:F4:20:1F
               SHA1:1F:CA:11:B7:52:91:CF:EB:E4:45:FF:48:1E:20:02:3B:FE:7C:29:AC
               签名算法名称:SHA1withRSA
               版本: 3
       信任这个认证？ [否]：  y
       认证已添加至keystore中

3、删除命令

      keytool -delete -alias emailcert -keystore "C:\Program Files (x86)\Java\jre6\lib\security\cacerts"

     -storepass changeit