spring-data-jpa-datatables

This project is an extension of the Spring Data JPA project to ease its use with jQuery plugin DataTables with server-side processing enabled.

This will allow you to handle the Ajax requests sent by DataTables for each draw of the information on the page (i.e. when paging, ordering, searching, etc.) from Spring @RestController.

For a MongoDB counterpart, please see spring-data-mongodb-datatables.

Example:

@RestController
public class UserRestController {

  @Autowired
  private UserRepository userRepository;

  @RequestMapping(value = "/data/users", method = RequestMethod.GET)
  public DataTablesOutput<User> getUsers(@Valid DataTablesInput input) {
    return userRepository.findAll(input);
  }
}

Contents

• Maven dependency
• Getting started
  • 1. Enable the use of DataTablesRepository factory
  • 2. Create a new entity
  • 3. Extend the DataTablesRepository interface
  • 4. On the client-side, create a new DataTable object
  • 5. Fix the serialization / deserialization of the query parameters
• API
• How to
  • Apply filters
  • Manage non-searchable fields
  • Limit the exposed attributes of the entities
• Troubleshooting

Maven dependency

<dependency>
  <groupId>com.github.darrachequesne</groupId>
  <artifactId>spring-data-jpa-datatables</artifactId>
  <version>5.0.0</version>
</dependency>

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Getting started

Please see the sample project for a complete example.

1. Enable the use of DataTablesRepository factory

With either

@Configuration
@EnableJpaRepositories(repositoryFactoryBeanClass = DataTablesRepositoryFactoryBean.class)
public class DataTablesConfiguration {}

or its XML counterpart

<jpa:repositories factory-class="org.springframework.data.jpa.datatables.repository.DataTablesRepositoryFactoryBean" />

You can restrict the scope of the factory with @EnableJpaRepositories(repositoryFactoryBeanClass = DataTablesRepositoryFactoryBean.class, basePackages = "my.package.for.datatables.repositories"). In that case, only the repositories in the given package will be instantiated as DataTablesRepositoryImpl on run.

@Configuration
@EnableJpaRepositories(basePackages = "my.default.package")
public class DefaultJpaConfiguration {}

@Configuration
@EnableJpaRepositories(repositoryFactoryBeanClass = DataTablesRepositoryFactoryBean.class, basePackages = "my.package.for.datatables.repositories")
public class DataTablesConfiguration {}

2. Create a new entity

@Entity
public class User {

  private Integer id;

  private String mail;

  @ManyToOne
  @JoinColumn(name = "id_address")
  private Address address;

}

3. Extend the DataTablesRepository interface

public interface UserRepository extends DataTablesRepository<User, Integer> {}

The DataTablesRepository interface extends both PagingAndSortingRepository and JpaSpecificationExecutor.

4. On the client-side, create a new DataTable object

$(document).ready(function() {
  var table = $('table#sample').DataTable({
    'ajax' : '/data/users',
    'serverSide' : true,
    columns : [{
      data : 'id'
    }, {
      data : 'mail'
    }, {
      data : 'address.town',
      render: function (data, type, row) {
        return data || '';
      }
    }]
  });
}

5. Fix the serialization / deserialization of the query parameters

By default, the parameters sent by the plugin cannot be deserialized by Spring MVC and will throw the following exception: InvalidPropertyException: Invalid property 'columns[0][data]' of bean class [org.springframework.data.jpa.datatables.mapping.DataTablesInput].

There are multiple solutions to this issue:

• include the jquery.spring-friendly.js file found at the root of the repository

It overrides jQuery data serialization to allow Spring MVC to correctly map input parameters (by changing column[0][data] into column[0].data in request payload)

• retrieve data with POST requests

Client-side:

$('table#sample').DataTable({
  'ajax': {
    'contentType': 'application/json',
    'url': '/data/users',
    'type': 'POST',
    'data': function(d) {
      return JSON.stringify(d);
    }
  }
})

Server-side:

@RequestMapping(value = "/data/users", method = RequestMethod.POST)
public DataTablesOutput<User> getUsers(@Valid @RequestBody DataTablesInput input) {
  return userRepository.findAll(input);
}

• manually serialize the query parameters

function flatten(params) {
  params.columns.forEach(function (column, index) {
    params['columns[' + index + '].data'] = column.data;
    params['columns[' + index + '].name'] = column.name;
    params['columns[' + index + '].searchable'] = column.searchable;
    params['columns[' + index + '].orderable'] = column.orderable;
    params['columns[' + index + '].search.regex'] = column.search.regex;
    params['columns[' + index + '].search.value'] = column.search.value;
  });
  delete params.columns;

  params.order.forEach(function (order, index) {
    params['order[' + index + '].column'] = order.column;
    params['order[' + index + '].dir'] = order.dir;
  });
  delete params.order;

  params['search.regex'] = params.search.regex;
  params['search.value'] = params.search.value;
  delete params.search;

  return params;
}

$('table#sample').DataTable({
  'ajax': {
    'url': '/data/users',
    'type': 'GET',
    'data': flatten
  }
})

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API

The repositories now expose the following methods:

DataTablesOutput<T> findAll(DataTablesInput input);
DataTablesOutput<R> findAll(DataTablesInput input, Function<T, R> converter);
DataTablesOutput<T> findAll(DataTablesInput input, Specification<T> additionalSpecification);

DataTablesOutput<T> findAll(DataTablesInput input, Specification<T> additionalSpecification,
    Specification<T> preFilteringSpecification);

DataTablesOutput<R> findAll(DataTablesInput input, Specification<T> additionalSpecification,
    Specification<T> preFilteringSpecification, Function<T, R> converter);

Note: since version 2.0, QueryDSL is also supported:

• replace DataTablesRepositoryFactoryBean with QDataTablesRepositoryFactoryBean
• replace DataTablesRepository with QDataTablesRepository

and your repositories will now expose:

DataTablesOutput<T> findAll(DataTablesInput input);
DataTablesOutput<R> findAll(DataTablesInput input, Function<T, R> converter);
DataTablesOutput<T> findAll(DataTablesInput input, Predicate additionalPredicate);

DataTablesOutput<T> findAll(DataTablesInput input, Predicate additionalPredicate,
    Predicate preFilteringPredicate);

DataTablesOutput<R> findAll(DataTablesInput input, Predicate additionalPredicate,
    Predicate preFilteringPredicate, Function<T, R> converter);

Your controllers should be able to handle the parameters sent by DataTables:

@RestController
public class UserRestController {

  @Autowired
  private UserRepository userRepository;

  @JsonView(DataTablesOutput.View.class)
  @RequestMapping(value = "/data/users", method = RequestMethod.GET)
  public DataTablesOutput<User> getUsers(@Valid DataTablesInput input) {
    return userRepository.findAll(input);
  }

  // or with some preprocessing
  @JsonView(DataTablesOutput.View.class)
  @RequestMapping(value = "/data/users", method = RequestMethod.GET)
  public DataTablesOutput<User> getUsers(@Valid DataTablesInput input) {
    ColumnParameter parameter0 = input.getColumns().get(0);
    Specification additionalSpecification = getAdditionalSpecification(parameter0.getSearch().getValue());
    parameter0.getSearch().setValue("");
    return userRepository.findAll(input, additionalSpecification);
  }

  // or with an additional filter allowing to 'hide' data from the client (the filter will be applied on both the count and the data queries, and may impact the recordsTotal in the output)
  @JsonView(DataTablesOutput.View.class)
  @RequestMapping(value = "/data/users", method = RequestMethod.GET)
  public DataTablesOutput<User> getUsers(@Valid DataTablesInput input) {
    return userRepository.findAll(input, null, removeHiddenEntitiesSpecification);
  }
}

The DataTablesInput class maps the fields sent by the client (listed there).

Spring documentation for Specification

How to

Apply filters

By default, the main search field is applied to all columns.

You can apply specific filter on a column with table.columns(<your column id>).search(<your filter>).draw(); (or table.columns(<your column name>:name)...) (see documentation).

Supported filters:

• Strings (WHERE <column> LIKE %<input>%)
• Booleans
• Array of values (WHERE <column> IN (<input>) where input is something like 'PARAM1+PARAM2+PARAM4')
• NULL values are also supported: 'PARAM1+PARAM3+NULL' becomes WHERE (<column> IN ('PARAM1', 'PARAM3') OR <column> IS NULL) (to actually search for 'NULL' string, please use \NULL)

Also supports paging and sorting.

Example:

{
  "draw": 1,
  "columns": [
    {
      "data": "id",
      "name": "",
      "searchable": true,
      "orderable": true,
      "search": {
        "value": "",
        "regex": false
      }
    },
    {
      "data": "firstName",
      "name": "",
      "searchable": true,
      "orderable": true,
      "search": {
        "value": "",
        "regex": false
      }
    },
    {
      "data": "lastName",
      "name": "",
      "searchable": true,
      "orderable": true,
      "search": {
        "value": "",
        "regex": false
      }
    }
  ],
  "order": [
    {
      "column": 0,
      "dir": "asc"
    }
  ],
  "start": 0,
  "length": 10,
  "search": {
    "value": "john",
    "regex": false
  }
}

is converted into the following SQL (through the Criteria API):

SELECT user0_.id AS id1_0_0_,
       user0_.first_name AS first_na3_0_0_,
       user0_.last_name AS last_nam4_0_0_
FROM users user0_
WHERE (user0_.id LIKE "%john%" OR user0_.first_name LIKE "%john%" OR user0_.last_name LIKE "%john%")
ORDER BY user0_.id ASC LIMIT 10

Note: the regex flag is currently ignored because JPQL only supports LIKE expressions (with % and _ tokens).

Yet you should be able to use the DBMS-specific regex operator with the CriteriaBuilder.function() method.

Example with H2 REGEXP_LIKE:

Column column = input.getColumn("my_column");
column.setSearchable(false); // so the default filter will not be applied
String regexValue = column.getSearch().getValue();
DataTablesOutput<...> output = repository.findAll(input, (root, query, builder) -> {
  Expression<String> regex = builder.function("REGEXP_LIKE", String.class, root.get("my_column"), builder.literal(regexValue));
  return builder.equal(regex, builder.literal(1));
});

Manage non-searchable fields

If you have a column that does not match an attribute on the server-side (for example, an 'Edit' button), you'll have to set the searchable and orderable attributes to false.

$(document).ready(function() {
  var table = $('table#sample').DataTable({
    'ajax' : '/data/users',
    'serverSide' : true,
    columns : [{
      data: 'id'
    }, {
      data: 'mail'
    }, {
      searchable: false,
      orderable: false
    }]
  });
}

Limit the exposed attributes of the entities

There are several ways to restrict the attributes of the entities on the server-side:

• using DTO

@RestController
public class UserRestController {

  @Autowired
  private UserRepository userRepository;

  @RequestMapping(value = "/data/users", method = RequestMethod.GET)
  public DataTablesOutput<UserDTO> getUsers(@Valid DataTablesInput input) {
    return userRepository.findAll(input, toUserDTO);
  }
}

• using @JsonView

@Entity
public class User {

  @JsonView(DataTablesOutput.View.class)
  private Integer id;

  // ignored
  private String mail;

}

@RestController
public class UserRestController {

  @Autowired
  private UserRepository userRepository;

  @JsonView(DataTablesOutput.View.class)
  @RequestMapping(value = "/data/users", method = RequestMethod.GET)
  public DataTablesOutput<User> getUsers(@Valid DataTablesInput input) {
    return userRepository.findAll(input);
  }
}

• using @JsonIgnore

@Entity
public class User {

  private Integer id;

  @JsonIgnore
  private String mail;

}

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Troubleshooting

• Invalid property 'columns[0][data]' of bean class [org.springframework.data.jpa.datatables.mapping.DataTablesInput]

Please see here.

• java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name ...

It seems you have a column with a data attribute that does not match the attribute of the @Entity on the server-side.

Please see here.

• java.lang.NoClassDefFoundError: org/hibernate/jpa/criteria/path/AbstractPathImpl

The versions >= 5.0.0 of the library are not compatible with Spring 4 (Spring Boot 1.x), please use the previous versions.

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