1.javabean反射
private User getUser(HttpServletRequest request) {
User user =null;
try {
user = new User();
//获取表单的map集合
Map<String, String[]> map = request.getParameterMap();
for(Map.Entry<String, String[]> m:map.entrySet()){
//获取单个param的name
String name = m.getKey();
//获取单个param的value
String[] values = m.getValue();
//属性描述器 通过反射机制
PropertyDescriptor pd = new PropertyDescriptor(name, User.class);
//获得这个param属性的set方法
Method method = pd.getWriteMethod();
//判断改param名字相同的值的个数是否为一个
if(values.length==1)
{
//获得该方法的参数类型列表
Class[] types = method.getParameterTypes();
//判断第一个参数的类型是否为数组
if(types[0].isArray())
{
//若是则以数组方式存入
method.invoke(user,(Object)new String[]{values[0]});
}
else
{
//若不是则以值方式存入
method.invoke(user, values[0]);
}
}
else
{
//不为一个就是数组 直接以数组方式存入
method.invoke(user, (Object)values);
}
}
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(user);
return user;
}
2.通过ThreadLocal实现sql事务的开启提交和回滚
public class ManagerThreadLocal {
private static ThreadLocal<Connection> tl=new ThreadLocal<>();//key value
public static Connection getConnection(){
Connection conn = tl.get();
if(conn==null){
conn= C3P0Util.getConnection();
tl.set(conn);
}
return conn;
}
//开启事务
public static void startTranscation(){
try {
getConnection().setAutoCommit(false);//begin
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//提交事务
public static void commit(){
try {
getConnection().commit();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//回滚事务
public static void rollback(){
try {
getConnection().rollback();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//释放资源
public static void close(){
try {
getConnection().close();//把连接还回连接池
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
3.Stl 用法
遍历详细博客:http://www.cppblog.com/biao/archive/2010/12/23/137257.html
</head>
<body>
<%
if(1==1){
out.print("a");
}
%>
<hr/>
<c:if test="${5<=5 }">
aaa
</c:if>
<hr/>
<c:set var="num" value="${2 }"></c:set>
<c:choose>
<c:when test="${num==1 }">aaa</c:when>
<c:when test="${num==2 }">bbb</c:when>
<c:when test="${num==3 }">ccc</c:when>
<c:otherwise>ddd</c:otherwise>
</c:choose>
<hr/>
<c:forEach var="i" begin="1" end="10" step="2" >
${i }<br/>
</c:forEach>
<hr/>
<%
List list=new ArrayList();
list.add("aaa");
list.add("bbb");
list.add("ccc");
list.add("ddd");
list.add("eee");
list.add("fff");
list.add("ooo");
request.setAttribute("list", list);
%>
<c:forEach items="${list} " var="i" >
${i }<br/>
</c:forEach>
<hr/>
<!-- 重点 -->
<table border="1">
<tr>
<td>数据</td>
<td>索引</td>
<td>计数</td>
<td>第一个</td>
<td>最后一个</td>
</tr>
<c:forEach items="${list }" var="l" varStatus="vs">
<%-- <tr ${vs.count%2==1?"style='background-color:lime'": "style='background-color:yellow'"}> --%>
<tr ${vs.count%2==1?"class='odd'":"class='even'" }>
<td>${l}</td>
<td>${vs.index }</td>
<td>${vs.count }</td>
<td>${vs.first }</td>
<td>${vs.last }</td>
</tr>
</c:forEach>
</table>
</body>
</html>
4.表单文件上传
import org.apache.commons.io.*;
import org.apache.commons.fileupload.*;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
// String name = request.getParameter("name");
// String phone = request.getParameter("phone");
// System.out.println(name);
// System.out.println(phone);
//由于表单 上传方式 enctype="multipart/form-data" request.getParameter("name");失效啦
// InputStream is = request.getInputStream();
// int len=0;
// byte [] buf=new byte[1024];
// while((len=is.read(buf))!=-1){
// System.out.println(new String(buf,0,len));
// }
//要执行文件上传操作
//1.首选判断 表单上传方式时候写的是 enctype="multipart/form-data"
boolean ismultipartContent = ServletFileUpload.isMultipartContent(request);
if(!ismultipartContent){
throw new RuntimeException(" you form is not multipart/form-data");
}
//1.创建DiskFileItemFactory对象
DiskFileItemFactory factory=new DiskFileItemFactory();
//指定临时文件存储的位置
factory.setRepository(new File("d:/aaa"));
//2.创建一个ServletFileUpload核心对象
ServletFileUpload sfu=new ServletFileUpload(factory);
//解决上传中文名乱码问题
sfu.setHeaderEncoding("UTF-8");
//3.解析request得到表单项集合
try {
//限制文件上传大小
//sfu.setFileSizeMax(1024*1024*3);//3M大小
//sfu.setSizeMax(1024*1024*6);//6M
List<FileItem> fileItems = sfu.parseRequest(request);
//遍历表单项的数据
for(FileItem fileItem:fileItems){
if(fileItem.isFormField()){//普通表单
//处理普通表单
processFormField(fileItem);
}else{//上传表单
processUploadField(fileItem);
}
}
}catch(FileUploadBase.FileSizeLimitExceededException e){
throw new RuntimeException("文件过大不能超过3M");
}catch(FileUploadBase.SizeLimitExceededException e){
throw new RuntimeException("总文件过大不能超过6M");
} catch (FileUploadException e) {
e.printStackTrace();
}
}
//处理文件上传
private void processUploadField(FileItem fileItem) {
//1上传的文件名
String filename = fileItem.getName();// 文件上传的值 1.jig a.txt D:1.jpg
//2.得到文件输入流
try {
// InputStream is = fileItem.getInputStream();
//通过输出流将上传文件保存到磁盘中
String directoryRealPath = this.getServletContext().getRealPath("/WEB-INF/upload");
File storeDirectory=new File(directoryRealPath);//即代表文件 也代表目录
if(!storeDirectory.exists()){
storeDirectory.mkdirs();//创建一个指定目录
}
//处理文件名
// filename=filename.substring(filename.lastIndexOf(File.separator)+1);
if(filename!=null){
filename = FilenameUtils.getName(filename);
}
//解决重名为题
filename=UUID.randomUUID()+"_"+filename;
//目录打散
//String childDirectory=makChildDirectory(storeDirectory);//2017-08-31
String childDirectory=makChildDirectory(storeDirectory,filename);
//构建一个完整路径
//File file=new File(storeDirectory,childDirectory+File.separator+filename);//upload/2017-08-31/1.jpg
//创建存储地方
/*FileOutputStream fos=new FileOutputStream(file);
int len=0;
byte [] buf=new byte[1024];
while((len=is.read(buf))!=-1){
fos.write(buf, 0, len);
}
fos.close();
is.close();*/
fileItem.write(new File(storeDirectory,childDirectory+File.separator+filename));
fileItem.delete();//清除临时缓存文件
} catch (Exception e) {
e.printStackTrace();
}
}
//优化打散方案
private String makChildDirectory(File storeDirectory, String filename) {
int hashCode = filename.hashCode();//字符串转换的32hashCode码
System.out.println(hashCode);
String code = Integer.toHexString(hashCode);//将哈希码转换为十六进制 0-9 a-f
System.out.println(code);
String childDirectory=code.charAt(0)+File.separator+code.charAt(1);
//创建指定目录
File file=new File(storeDirectory,childDirectory);
if(!file.exists()){
file.mkdirs();
}
return childDirectory;
}
//按照日期打散
private String makChildDirectory(File storeDirectory) {
//以日期创建文件夹
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");//2017-08-31
String dateDirectory = sdf.format(new Date());
//只管创建目录
File file=new File(storeDirectory,dateDirectory);// /upload/2017-08-31
if(!file.exists()){
file.mkdirs();
}
return dateDirectory;//2017-08-31
}
//处理普通表单
private void processFormField(FileItem fileItem) {
try {
String fieldname = fileItem.getFieldName();//name
String fieldvalue = fileItem.getString("UTF-8");//如果里面不写utf-8则乱码
// fieldvalue=new String(fieldvalue.getBytes("ISO-8859-1"),"UTF-8"); //解决乱码方法2
//String fieldvalue=fileItem.getString("UTf-8");
System.out.println(fieldname+" "+fieldvalue);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
5.文件下载
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String filename = "下载订单.csv";
//设置文件名的编码
filename = new String(filename.getBytes("GBK"),"ISO-8859-1");
//告诉浏览器要下载文件
response.setHeader("content-disposition", "attachment;filename="+filename);
// response.setHeader("content-type", "image/jpeg");//下载图片
response.setContentType(this.getServletContext().getMimeType(filename));//下载filename类型的文件
//告知服务器使用编码格式
response.setCharacterEncoding("GBK");
//调用业务逻辑
//查询数据库 订单表
//创建输出流
PrintWriter out = response.getWriter();
out.print("牙具，20
");
out.print("毛巾，210
");
out.print("牙膏，100
");
}
6.jquery之ajax
一.邮箱验证
$("#email").blur(function(){
var email = $(this).val();
var params = {"email":email};
var url = "${pageContext.request.contextPath }/servlet/userServlet?method=emailExp";
var regexp = /^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-])+/;
if(regexp.test(email))
{
$.ajax(
{
url:url,
type:"post",
data:params,
success:function(d){
if("1"==d)
{
$("#emailMsg").html("邮箱已被注册");
$("#emailMsg").css("color","red");
$("#btn_active").attr("disabled","disabled");
}
else
{
$("#emailMsg").html("邮箱可以使用");
$("#emailMsg").css("color","green");
$("#btn_active").removeAttr("disabled");
}
},
error:function(d){},
dataType:"text"
}
);
}else
{
$("#emailMsg").html("邮箱格式不正确");
$("#emailMsg").css("color","red");
$("#btn_active").attr("disabled","disabled");
}
});
二.input查询数据回显
$bkmg = $(".searchArticleResultList");
$(".queryString").keyup(function(){
var title = $(this).val();
var params = {"title":title};
var url="${pageContext.request.contextPath }/TopicServlet?method=serchBackMsg";
$.ajax({
url:url,
type:"post",
data:params,
success:function(d){
/*for(var i=0;i<d.length;i++)
{
var date = d[i];
alert(date.title);
} */
$bkmg.css("display","block");
$(d).each(function(){
$bkmg.append("<div onmousedown='mydown(this)' onmouseout='myout(this)' onmousemove='mymove(this)'>"+this.title+"</div>");
});
},error:function(obj){},
dataType: "json"
});
});
$(".queryString").blur(function(){
$bkmg.empty();
$bkmg.css("display","none");
});
function mydown(d){
$bkmg.empty();
$bkmg.css("display","none");
$(".queryString").val($(d).text());
}
function myout(d){
$(d).css("background","white");
}
function mymove(d){
$(d).css("background","gray");
}
7.form表单中input type为submit.button的控件和button控件点击不提交表单的处理方案
即在其onclick事件中添加return false语句即可
(1).<button onclick="history.go(-1);return false;">返回</button> (2).<input type="submit" value="返回" onclick="history.go(-1);return false;"/>