///打印异常信息  尤其是运行时异常  比getMessage()更详细
public static String getMessageInfo(Exception e){
    OutputStream ops =new ByteArrayOutputStream();
    PrintStream ps=new PrintStream(ops);
    e.printStackTrace(ps);
    ps.close();
    try {
        ops.close();
    } catch (IOException e1) {
        e1.printStackTrace();
    }finally {
        return ops.toString();
    }
}