如何修复“不兼容类型”？我正在编译这个Java程序的错误？ [英] How Do I Fix The "Incompatible Type" Error That I Am Getting On Compiling This Java Program?

问题描述

package join;
import java.sql.*;
import java.util.*;
import connection.*;
import java.util.ArrayList;

public class Course
{
	private String student_mail_add="",student_password="";
	Connection con=null;

ArrayList<string> course_id= new ArrayList<string>();
ArrayList<string> course_name = new ArrayList<string>();
	
public static ArrayList<string> convertStringArrayToArraylist(String[] strArr){
    ArrayList<string> stringList = new ArrayList<string>();
    for (String s : strArr) {
        stringList.add(s);
    }
    return stringList;
}	
	
	public void setStudent_mail_add(String student_mail_add) {
	this.student_mail_add=student_mail_add;
	}
	public String getStudent_mail_add()
	{
	return student_mail_add;
	}
	

	public void setStudent_password(String student_password) {
	this.student_password=student_password;
	}
	public String getStudent_password()
	{
	return student_password;
	}
	

	public void setCourse_id(String course_id) {
	this.course_id=course_id;
	}
	public String getCourse_id()
	{
	return course_id;
	}


	public void setCourse_name(String course_name) {
	this.course_name = course_name;
	}
	public String getCourse_name()
	{
	return course_name;
	}	

	public void fetch()
	{
		try
		{
		  Connect ob=new Connect();
		  con=ob.ctest();
		  PreparedStatement pst=con.prepareStatement("select * from course_join where course_join.student_mail_add=student_profile.student_mail_add=?");
		  pst.setString(1,student_mail_add);
		  ResultSet rs=pst.executeQuery();

		  while(rs.next()){
		   student_mail_add=rs.getString(1);
		  student_password=rs.getString(2);
		 
		  course_id.add(rs.getString(3));
		course_name.add(rs.getString(4));

			            }
		con.close();
		}
		catch(Exception e){}
	}
	

public int delete()
	{
	int t=0;
	try{
		Connect ob=new Connect();
		con=ob.ctest();
		PreparedStatement pst=con.prepareStatement("delete from course_join where student_mail_add=?");
		pst.setString(1,student_mail_add);
		
		t=pst.executeUpdate();
		con.close();
	}

	catch(Exception e){}
	return t;
	}

	}

推荐答案

您可能希望看到更多问题：

You might want to see more of your problem:

   try{
    Connect ob=new Connect();
    con=ob.ctest();
    PreparedStatement pst=con.prepareStatement("delete from course_join where student_mail_add=?");
    pst.setString(1,student_mail_add);

    t=pst.executeUpdate();
    con.close();
}

catch(Exception e){
        // DO NOT SUPPRESS EXCEPTIONS!
        e.printStackTrace(); // or logging or anything, but never completely suppress them.
    }

您是手动编码还是使用正确的IDE？

导入是手动的。请使用IDE，eclipse以及netbeans都是免费的。他们会引导你解决没有正确参考的问题。







你可能想要检查如何从ArrayList返回一个数组：

And do you code manually or do you use a proper IDE?
The imports are manual. Please use an IDE, eclipse as also netbeans are free. They will guide you through that problem of not having the correct reference.



You might want to check on how to return an Array from an ArrayList:

public static ArrayList<string> convertStringArrayToArraylist(String[] strArr){
    ArrayList<string> stringList = new ArrayList<string>();
    for (String s : strArr) {
        stringList.add(s);
    }
    return stringList;
}	</string></string></string>

http://docs.oracle.com/javase/7/docs/api/java/util /ArrayList.html#toArray（） [ ^ ]

我手动编写代码..当我在64位的另一台计算机上编译它时，它可以完美编译..我似乎无法在我的电脑中找到错误

i do code manually..when i am compiling this on another computer of 64bits it gets compiled flawlessly.. i just cant seem to find the error in my computer

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