freemarker中显示某对象使用${name}.
但如果name为null。如果需要判断对象是否为空:
<#if name??>
……
</#if>
当然也可以通过设置默认值${name!''}来避免对象为空的错误。如果name为空,就以默认值(“!”后的字符)显示。
user,name都有可能为空,那么可以写成${(user.name)!''},表示user或者name为null,都显示为空。
判断为空
<#if (user.name)??>
……
</#if>
List insNoticeDtoList=JSONObject.parseObject(strInsNotices,List.class); //json字符串转List
JSONObject jsobj=(JSONObject)JSONObject.toJSON(map); //map 转为json对象。再将json转字符串。
String tt=jsobj.toJSONString();
//requst 参数转MAP
Gson json = new Gson();
Map<String,String> mapData2 = json.fromJson(request.getParameter("data"), new TypeToken<Map<String,String>>(){}.getType());
//读取文件乱码
bufferedreader = new BufferedReader(new FileReader(filename));
//改写,指定编码格式
BufferedReader br=new BufferedReader(new InputStreamReader(new FileInputStream(fileName),"UTF-8"));
//输出文件编码
File outFile = new File(targetFile);
Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outFile),"UTF-8"));
解决TOMCAT内存溢出
set JAVA_OPTS=%JAVA_OPTS% %LOGGING_MANAGER% -Xms512m -Xmx1024m -XX:MaxNewSize=256m -XX:PermSize=64M -XX:MaxPermSize=256m
线程快速简单写法
new Thread(new TestThread()).start();
内部类:
class TestThread implements Runnable{
@Override
public void run(){
}
}
sql语句
insert into NEED_RESEND values (sys_guid(),'10',
to_timestamp('2015-05-20 11:17:25.287','yyyy-MM-dd HH24:MI:ss.ff'),
to_timestamp('2015-05-20 11:17:25.287','yyyy-MM-dd HH24:MI:ss.ff'),'6','第三次补数失败!');
Mybatis传多个参数(三种解决方案)
1、PublicUserselectUser(Stringname,String area);
<selectid="selectUser"resultMap="BaseResultMap">
select * fromuser_user_t whereuser_name = #{0}anduser_area=#{1}
</select>
2、PublicUserselectUser(Map paramMap);
resultMap="BaseResultMap">
select * fromuser_user_t whereuser_name = #{userName,jdbcType=VARCHAR}anduser_area=#{userArea,jdbcType=VARCHAR}
</select>
3、PublicUserselectUser(@param(“userName”)Stringname,@param(“userArea”)String area);
<selectid=" selectUser"resultMap="BaseResultMap">
select * fromuser_user_t whereuser_name = #{userName,jdbcType=VARCHAR}anduser_area=#{userArea,jdbcType=VARCHAR}
</select>
mybatis 返回结果
1、自定义的Bean Map对象, resultMap要预先定义
<select id="getResourcesInfoPage" parameterType="Map" resultMap="ExtResultMap" >
2、sql 返回的字段名Map对象
<select id="getResourcesInfoPage" parameterType="Map" resultType="Map" >
spring 方法自定义跳转
@RequestMapping(value = "/getWordXmlJsp")
public @ResponseBody
void getWordXmlJsp(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
String url="/fileupload/template-xuqiu-format3.xml";
RequestDispatcher rd = request.getServletContext().getRequestDispatcher(url);
request.getServletContext().setAttribute("name", "788");
rd.forward(request, response);
}
<!-- 登录拦截器 3.0用这种方式 -->
<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
<property name="interceptors">
<list>
<ref bean="loginInterceptor"/> <!--这是你自定义的拦截器 -->
</list>
</property>
</bean>
<bean id="loginInterceptor" class="com.xpoplarsoft.interceptor.LoginInterceptor"/>
清理word插件缓存
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Bin>mage -cc
//拖动图标的位置偏移
mxUtils.makeDraggable(a,this.editor.graph,b,c,-c.width,-c.height);
<add as="Start" template="start" style="symbol;image=images/symbols/event.png" icon="images/start_2.png" pressedIcon="images/arrow_2.png"><![CDATA[
//在鼠标单击时执行的函数
function (editor, cell, evt, targetCell)
{
var pt = mxUtils.convertPoint(editor.graph.container, mxEvent.getClientX(evt),mxEvent.getClientY(evt));
return editor.addVertex(targetCell, cell, pt.x-(cell.geometry.width/2), pt.y-(cell.geometry.height/2));
}
]]></add>
广播IP地址:想要参与组播的所有机器可以“加入”这个地址,任意一台机器只要向该地址发送信息,那么该信息就会自动广播给所有“加入”到该地址的机器上,也就是说这个神秘的广播IP地址仿佛是一个虚拟的服务器,它履行着我们之前TCP群聊的服务器的功能
byte data[] = new byte[65535];
DatagramPacket packet = new DatagramPacket(data, data.length);
multicastSocket.receive(packet);
int dataLen = packet.getLength();
byte[] dataBuf = new byte[dataLen];
System.arraycopy(data, 0, dataBuf, 0, dataLen);
电脑自动重启是什么原因,电脑自动重启什么解决
https://jingyan.baidu.com/article/ab69b2706d5a182ca6189f4c.html