Way to store MySQL data into java objects

Question

I'm working on a project where I would need to write a program to take in data from MySql into a java program then save that data into an object to be used later. I already managed to set up the JDBC connection to the MySql database and get all the information from the database as well as being able to write queries to the DB. What I want to do now is store that information into an object. So, I created a table called people with the columns name and age that contain information. In my program, I have a people class with the name and age fields shown below

public class People {
private String name;
private int age;


public people(String name, int age) {
    this.name = name;
    this.age =age;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

@Override
public String toString() {
    return "people{" +
            "name='" + name + '\'' +
            ", age=" + age +
            '}';
}

}

I'm wondering how I could take the MySQL data that I imported and using this people class create objects from it?

Did you try executing a SELECT PreparedStatement (or Statement), iterating over the ResultSet and constructing People objects for each row in the result set? — terrorrussia-keeps-killing
– terrorrussia-keeps-killing, Commented Dec 2, 2020 at 20:35

Kyrillus K · Accepted Answer · 2020-12-02 20:44:37Z

3

You should map your Person class with the @Entity to your db table(https://www.baeldung.com/jpa-entity-table-names) and create a TypedQuery(https://www.objectdb.com/java/jpa/query/api) and select all entries in the Database. Or you could just create a normal Query and parse the resultList to a list of peoples.

edited Dec 2, 2020 at 20:44

answered Dec 2, 2020 at 20:35

Kyrillus K

355 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

terrorrussia-keeps-killing Over a year ago

The OP is (most likely) asking on how it could be done with the very basic manner. I believe there is no need suggesting heavy-weight tools like ORMs for this case.

Kyrillus K Over a year ago

Yeah I agree, that's why I described the fancy and the simple way so he can choose what he wants.

boldercoder Over a year ago

Alright, thanks. I think i'll start with the simple PreparedStatement option first and see how that works

eis Over a year ago

@fluffy funny, my first thought when reading the question is that o/r-mapper was exactly the thing asked here

terrorrussia-keeps-killing Over a year ago

@eis I agree that the OP was not very clear on that, but JPA is not the only ORM-related way around. But yeah, I was just guessing.

Twistleton · Accepted Answer · 2020-12-03 08:26:43Z

2

A very primitive solution could look like this:

    String sql  = " select name         " +
                  "      , age          " +               
                  "   from TABLE_PEOPLE ";
    
    ArrayList<People> staffs = new ArrayList<>();

    try {
        Connection connection = dataSource.getConnection();
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        ResultSet resultSet = preparedStatement.executeQuery();
        while (resultSet.next()) {
            People people = new People(resultSet.getString("name"),
                                       resultSet.getInt("age"));
            staffs.add(people);
        }
        resultSet.close();
        preparedStatement.close();
        connection.close();

An important note: Your constructor is wrong. A constructor starts with a capital letter.

 public People(String name, int age) {
    this.name = name;
    this.age = age;
 }

edited Dec 3, 2020 at 8:26

answered Dec 3, 2020 at 7:36

Twistleton

2,9665 gold badges31 silver badges40 bronze badges

2 Comments

terrorrussia-keeps-killing Over a year ago

I would suggest using try-with-resources, because the current answer may lead to resource leaks in case of at least resultSet methods throw an exception.

Twistleton Over a year ago

@fluffy I agree. I did not program it that way for a long time. Today I do that with Spring Data JPA.

Collectives™ on Stack Overflow

Way to store MySQL data into java objects

2 Answers 2

5 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related