以下示例用java实现ping，然后用PLSQL存储过程调用该方法，可用来测试dblink服务器网络状态

1.java调用系统功能实现ping，返回ping后获取的字符（以下代码在Linux上通过，windows的话需要修改参数）

create or replace and compile java source named "CheckNet" asimport java.net.*;import java.io.*;import java.util.*;public class CheckNet{    public static String ping(String host) {    String pingResult = "";    String pingCmd = "ping -c 2 " + host;     BufferedReader in;    try {      Runtime r = Runtime.getRuntime();      Process p = r.exec(pingCmd);      in = new BufferedReader(new      InputStreamReader(p.getInputStream()));      String inputLine;      while ((inputLine = in.readLine()) != null) {        pingResult += inputLine;       }      in.close();      return pingResult;      }     catch (IOException e) {        return e.getMessage();     }   }}

2.用PLSQL封装java方法

CREATE OR REPLACE FUNCTION CheckNet_ping(p_host in varchar2) RETURN varchar2 AS    LANGUAGE JAVA NAME 'CheckNet.ping(java.lang.String) return java.lang.String';

3.测试

select CheckNet_ping('127.0.0.1') from dual