OAuthCallback_2.page

 <apex:form id="fm">
    <apex:outputPanel rendered="{!NOT(ISNULL(resBody))}">
      <apex:pageBlock >
        <apex:commandButton action="{!getAccounts}" value="取引先を取得" reRender="fm" />
        <apex:pageBlockTable id="pbtAccounts" 
            value="{!accounts}" var="acc" rendered="{!NOT(ISNULL(accounts))}">
          <apex:column value="{!acc.Id}" />
          <apex:column value="{!acc.Name}" />
        </apex:pageBlockTable>
      </apex:pageBlock>
    </apex:outputPanel>
  </apex:form>