j16

/*

1. Write a java program to create a TreeSet, add some colors (String) and print out the
   content of TreeSet in ascending order
   */
   package com.mycompany.javaslip;

import java.util.*;

public class slip16_1

{
public static void main(String[] args) {
Set<String> colors = new TreeSet<>();

    colors.add("Red");
    colors.add("Blue");
    colors.add("Green");
    colors.add("Yellow");
    colors.add("Black");
    
    System.out.println(colors);
}

}

/*
Write a Java program to accept the details of Teacher (TNo, TName, Subject). Insert at
least 5 Records into Teacher Table and display the details of Teacher who is teaching
“JAVA” Subject. (Use PreparedStatement Interface)
*/
package com.mycompany.javaslip;

import java.sql.*;
import java.util.Scanner;

class Teacher {

Teacher() throws SQLException, SQLException {
    Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres", "postgres", "postgres");
    
    for(int i=0; i<5; i++)
        insert(conn);
    
    select(conn);
}

private void insert(Connection conn) throws SQLException {
    String sql = "insert into teacher values(?, ?, ?)";
    
    PreparedStatement ps = conn.prepareStatement(sql);
    
    Scanner sc = new Scanner(System.in);
    
    System.out.println("Enter tno:");
    ps.setInt(1, sc.nextInt());
    sc.nextLine();
    
    System.out.println("Enter tname:");
    ps.setString(2, sc.nextLine());
    
    System.out.println("Enter subject:");
    ps.setString(3, sc.nextLine());
    
    ps.executeUpdate();
}

private void select(Connection conn) throws SQLException {
    String sql = "select * from teacher where subject = 'java'";
    
    Statement stmt = conn.createStatement();
    
    ResultSet rs = stmt.executeQuery(sql);
    while(rs.next()) {
        System.out.println("teacher tno: " + rs.getInt("tno"));
        System.out.println("teacher tname: " + rs.getString("tname"));
        System.out.println("teacher subject: " + rs.getString("subject"));
    }
}

}

public class slip16_2
{
public static void main(String[] args) throws SQLException {
new Teacher();
}
}