I have been searching left and right but still can't find a good solution to this. Also I'm pretty new to programing so please excuse the way I describe thing :). I'm using Spring, MySQL, Java, Thymeleaf.

Basically, I have a list of object passed from the controller:

[person [code=1, name=A, car=ford1],person [id=2, name=A, car=ford2], person [id=1, name=B, car=toyota1], person [id=2, name=B, car=toyota2] ]

I want to display this data using Thymeleaf in either an HTML table or bootstrap grid system.

This is what I got:

<div>
    <table
      
    >
      <thead >
        <tr>
          <th>ID</th>
          <th>Name</th>
          <th>Car</th>
           <th>Name</th>
          <th>Car</th>
        </tr>
      </thead>
      <tbody>
        <tr th:each="person :${listOfPerson}">
          <td>
            [[${person.id}]]
          </td>
          <td>
            [[${person.name}]]
          </td>
          <td>
            [[${person.car}]]
          </td>
        </tr>
      </tbody>
    </table>
  </div>

so this display the data like this:

but I want it to display like this:

I think I probably need to somehow split this data into id 1 and id 2. Here is two ways I could think of doing this:

• Using Thymeleaf th:if="${person.id.equals(1)} to get the data for id 1 and then repeat for 2, I just don't know how to put this into the table.
• format the data using a query, I'm not sure how to do this without turning the result into one single column with GROUP_CONCAT.

Maybe I need to change the SQL table, please give me some suggestion.

Edit: So I think I found the answer to this MySQL pivot

CodePudding user response：

Group your list of persons by id. Let's say you have a list like this:

List<Person> persons = Arrays.asList(
    new Person(1, "A", "ford1"),
    new Person(2, "A", "ford2"),
    new Person(1, "B", "toyota1"),
    new Person(2, "B", "toyota2")
)

Group it:

Map<Integer, List<Person>> groupedByIdPersons = persons.stream().collect(Collectors.groupingBy(Person::getId));

Use it in Thymeleaf:

1. Iterate over whole map in th:block to create header. Repeats as many times as there are collections grouped by the id.

2. Iterate over whole map to extract both key/value, then iterate only over values in th:block

<thead>
    <tr>
        <th:block th:each="elem : ${groupedByIdPersons}">
            <th>ID</th>
            <th>Name</th>
            <th>Car</th>
        </th:block>
    </tr>
</thead>
<tbody>
    <tr th:each="elem : ${groupedByIdPersons}">
        <th:block th:each="person : ${elem.value}">
            <td>${person.id}</td>
            <td>${person.name}</td>
            <td>${person.car}</td>
        </th:block>
    </tr>
</tbody>