java上传图片到虚拟路径，简单反射

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 fileItems=null;
upload.setFileSizeMax(102410245);
upload.setSizeMax(102410241);
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 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" %>

映射

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