1.配置tomcat，还有依赖包
进入配置。
选择一个空文件夹作为虚拟路径，配置好下载所需的jar包，点击这可下载
起名字最好是：commons-beanutils-1.8.0
点击+，导入刚刚的五个jar包
2.编写UploadServlet
点击查看的代码
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Random;
import javax.servlet.ServletException;
@WebServlet(urlPatterns = "/upload")
public class UploadServlet extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
FileItemFactory factory=new DiskFileItemFactory();
ServletFileUpload upload=new ServletFileUpload(factory);
List<FileItem> fileItems=null;
upload.setFileSizeMax(1024*1024*5);
upload.setSizeMax(1024*1024*1);
try {
fileItems=upload.parseRequest(req);
} catch (FileUploadException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for (FileItem fileItem : fileItems) {
if (fileItem.isFormField()) {
String fieldName=fileItem.getFieldName();
String value=fileItem.getString("utf-8");
System.out.println(fieldName+":"+value);
} else {
String uploadPath="E://files";
File uploadFile=new File(fileItem.getName());
String fileName=uploadFile.getName();
if (fileName.lastIndexOf(".")!=-1) {
String exist=fileName.substring(fileName.lastIndexOf("."));
Random random=new Random();
fileName=System.currentTimeMillis()+""+(random.nextInt(9000)+1000)+exist;
File destFile=new File(uploadPath,fileName);
try {
fileItem.write(destFile);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(uploadPath+"//"+fileName);
}
resp.sendRedirect("http://127.0.0.1:8080/files/"+fileName);
}
}
}
}
3.编写LoginServlet
点击查看的代码
import java.io.IOException;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.izhicheng.dao.User;
import net.sf.json.JSONObject;
@WebServlet(urlPatterns = "/login")
public class LoginServlet extends HttpServlet{
public static <E> E getBean(Class cl,HttpServletRequest req) {
E obj =null;
try {
obj=(E) cl.newInstance();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Field[] fields=cl.getDeclaredFields();
for (Field field : fields) {
String value=req.getParameter(field.getName());
if (value!=null) {
field.setAccessible(true);
try {
if (field.getType().equals(Integer.class)) {
field.set(obj, Integer.valueOf(value));
}else if (field.getType().equals(String.class)) {
field.set(obj, value);
}else if (field.getType().equals(BigDecimal.class)) {
field.set(obj, new BigDecimal(value));
}
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return obj;
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
User user=getBean(User.class,req);
System.out.println(user);
resp.setContentType("application/json;charset=utf-8");
resp.getWriter().write(user.toString());
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
}
4.编写User
点击查看的代码
import java.math.BigInteger;
public class User {
String name;
Integer id;
BigInteger coin;
@Override
public String toString() {
return "User{" +
"name='" + name + '/'' +
", age=" + id +
", coin=" + coin +
'}';
}
public User() {
this.name = "wm";
this.id = 1;
this.coin = BigInteger.valueOf(50);
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return id;
}
public void setAge(Integer age) {
this.id = age;
}
public BigInteger getCoin() {
return coin;
}
public void setCoin(BigInteger coin) {
this.coin = coin;
}
}
5.编写前端代码upload.jsp
点击查看的代码
<%@ page contentType="text/html;charset=UTF-8" %>
<html>
<head>
<title>Second assignment</title>
</head>
<body>
<form action='http://127.0.0.1:8080/upload' method='POST' enctype='multipart/form-data'>
<label>
<input type='text' name='name'/>
</label>
<br>
<input type='file' name='file' id='file' style='display:none'/>
<img style='width:200px;height:200px;' id='img' alt="" src=""/>
<input type='submit' />
</form>
<a href="/login">映射</a>
</body>
<script>
document.getElementById("img").onclick=function(){
document.getElementById("file").click();
}
document.getElementById("file").onchange=function(){
const f = this.files[0];
const fr = new FileReader();
fr.readAsDataURL(f);
fr.onload=function(){
document.getElementById('img').src=this.result;
}
}
</script>
</html>
6效果图
自己修改下路径与虚拟路径，jsp在主页写一个
<a href="upload.jsp">登入</a>跳过来
原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/288470.html