无法通过Struts2中的jdbc从数据库存储和检索图像数据
发布于 2021-02-01 16:18:09
我正在使用struts2。我试图将图像的路径存储到数据库中并将图像存储在服务器中，然后想要在jsp页面中检索这些图像数据。我需要指导。但我得到一个错误
java.lang.NullPointerException
我创建了3个班级。注册（bean类）registrationService（jdbc代码）registrationaction
注册.java
public class Registration{
private String first_name;
private String last_name;
private String gender;
private String email_id;
private String password;
private String dob;
private String father_name;
private String mother_name;
private String contact;
private String mobile;
private String address;
private String city;
private String country;
private String graduation;
private String graduate_school_mark;
private String graduation_year;
private String inter_school;
private String inter_school_mark;
private String inter_year;
private String high_school;
private String high_school_mark;
private String high_school_year;
private String role;
private String salary;
private File fphoto;
private File fresume;
private String pre_company;
// getter和setter
RegistrationService.java
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import org.apache.struts2.ServletActionContext;
public class RegistrationService {
public boolean filledRegistration(Registration registration) throws SQLException, ClassNotFoundException, FileNotFoundException, IOException{
Class.forName("com.mysql.jdbc.Driver");
Connection con= DriverManager.getConnection("jdbc:mysql://localhost:3306/erp","root","ali$");
String sql = "insert into registration(first_name,last_name,password,gender,email_id,dob,"
+ "father_name,mother_name,contact,mobile,address,city,country,graduation,"
+ "graduation_marks,graduation_year,inter,inter_marks,inter_year,high_school,"
+ "high_marks,high_year,role,salary,resume,photo,pre_comp) value(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement p= con.prepareStatement(sql);
p.setString(1,registration.getFirst_name());
p.setString(2,registration.getLast_name());
p.setString(3,registration.getPassword());
p.setString(4,registration.getGender());
p.setString(5,registration.getEmail_id());
p.setString(6,registration.getDob());
p.setString(7,registration.getFather_name());
p.setString(8,registration.getMother_name());
p.setString(9,registration.getContact());
p.setString(10,registration.getMobile());
p.setString(11,registration.getAddress());
p.setString(12,registration.getCity());
p.setString(13,registration.getCountry());
p.setString(14,registration.getGraduation());
p.setString(15,registration.getGraduate_school_mark());
p.setString(16,registration.getGraduation_year());
p.setString(17,registration.getInter_school());
p.setString(18,registration.getInter_school_mark());
p.setString(19,registration.getInter_year());
p.setString(20,registration.getHigh_school());
p.setString(21,registration.getHigh_school_mark());
p.setString(22,registration.getHigh_school_year());
p.setString(23,registration.getRole());
p.setString(24,registration.getSalary());
FileInputStream fis1 = new FileInputStream(registration.getFphoto());
p.setBinaryStream(25,fis1);
FileInputStream fis=new FileInputStream(registration.getFphoto());
p.setBinaryStream(26, fis);
p.setString(27,registration.getPre_company());
String s= ServletActionContext.getRequest().getRealPath("");
System.out.println(s);
int temp= s.lastIndexOf("\\");
String s1= s.substring(0, temp);
// System.out.println("---------->"+s1);
int temp1 = s1.lastIndexOf("\\");
String s2= s1.substring(0, temp1);
FileOutputStream fos=new FileOutputStream(s2+"\\web\\Images\\image"+registration.getEmail_id()+".jpg");
byte buffer[]=new byte[1024];
int read=0;
while((read=fis.read(buffer, 0, 1024))!=-1){
fos.write(buffer);
}
fis.close();
fos.close();
int i= p.executeUpdate();
if(i>0){
return true;
}
return false;
}
}
RegistrationAction.java
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
import java.io.IOException;
import java.sql.SQLException;
public class RegistrationAction extends ActionSupport implements ModelDriven{
Registration registration=new Registration();
public Registration getRegistration() {
return registration;
}
public void setRegistration(Registration registration) {
this.registration = registration;
}
@Override
public String execute() throws ClassNotFoundException, SQLException, IOException{
RegistrationService rs= new RegistrationService();
if( rs.filledRegistration(registration)){
return "registered";
} else {
}
return "failed";
}
@Override
public Object getModel() {
return registration;
}
}
welcome.jsp
<%@taglib uri="/struts-tags" prefix="s"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<s:property value="user.email"/>
<s:property value="user."/>
<h1>Welcome</h1>
<s:property value="user.user_name"/>
<s:form action="logoutAction">
<s:submit value="logout"/>
<%
String s=(String)request.getContextPath();
String path=s+"/Images/"+user.email+".jpg";
%>
<img src="<%=path%>" width="200" height="200" />
</s:form>
</body>
</html>
玻璃鱼服务器
Severe: Exception occurred during processing request: null
java.lang.NullPointerException
at java.io.FileInputStream.<init>(FileInputStream.java:130)
at package_registration.RegistrationService.filledRegistration(RegistrationService.java:53)
at package_registration.RegistrationAction.execute(RegistrationAction.java:25)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:450)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:289)
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1 个回答
-
满足您要求的正确设计是：-
1）将图像路径存储到数据库。
2）将图像存储在服务器中，并使用路径访问这些图像。现在，您的Registration类的fphoto应该为String类型。因为您要存储图像路径，而不是将实际图像存储在db中。
获得文件路径后，创建一个File对象，并将其传递给FileOutputStream，该文件可用于在jsp上显示图像。
