spring-boot-jpa-sample

Sample spring boot application demonstrating the generic usage of JPA APIs & to be able to query easily.

How to Run?

---

Before you run the application have a DB up & running & provide the details accordingly in the application.yml (src /resource folder)

spring: datasource: url: jdbc:postgresql://YOURHOST:5432/spring-jpa username: postgres password: postgres

Run ./run.sh - A spring boot application will be hosted on http://localhost:8881

Upload Sample Data:

---

The persons.json file is present in test folder resources, you can use the following API to store the data.

POST: http://localhost:8881/persons

BODY: The file content - JSON array

How to Query?

---

List persons: GET Method:

1. http://localhost:8881/persons?age=30
2. http://localhost:8881/persons?age:lt=30
3. http://localhost:8881/persons?name:like=Dunlap
4. http://localhost:8881/persons?dob:btw=millis1,millis2 # Time in Millis

The following opertions are supported:

public enum Operation {

    /**
     * equalTo & notEqualTo
     */
    eq, ne,

    /**
     * Text operaions: Like / Contains text
     */
    cn, // Contains
    like, // Like
    sw, // startsWith
    ew, // endsWith

    /**
     * LessThan, GreaterThan, LessThanOrEqualTo & GreaterThanOrEqualTo
     */
    lt, gt, le, ge,

    /**
     * Between range.
     * For eg. { "field": "dob", "op": "btw", "value": [1544725100000, 1544725900000 ]}
     * Fetch records between a range of two dates. The date can be a String ("2020-03-03"),
     * a Long (timeInMillis) or an instance of {@link java.util.Date} itself.
     *
     * The range can also be a normal on usual Strings or Numbers.
     * For eg.
     * { "field": "age", "op": "btw", "value": [15, 25 ]} - Age between 15 to 25
     * { "field": "name", "op": "btw", "value": ["a", "f" ]} - Name between 'a' & 'f'
     */
    btw
}

POST Method:

1. http://localhost:8881/persons/json?sort=age&page=0&size=20

   Body: {"filters":[{"field":"age","value":30}]} # The Operation EQ is default

2. http://localhost:8881/persons/json?sort=age&page=0&size=20

   Body: {"filters":[{"field":"age","op":"LT","value":30}]}

For more details, please refer the API details below.

API Details:

---

It has a com.maqs.springboot.sample.repository.SpecificationBuilder that translates the com.maqs.springboot.sample.dto.SearchCriteria DTO object & prepares a collection of Predicates.

For. eg. Create a search criteria on Person entity to filter by age who are less than 30. The JSON below would fetch the persons whose age is less than 30.

SearchCriteria searchCriteria = new SearchCriteria();

SearchCriteria.Filter age30 = new SearchCriteria.Filter(field, SearchCriteria.Operation.LT, value); searchCriteria.addFilter(age30);

The above criteria is equivalent to the following JSON:

{"filters":[{"field":"age","op":"LT","value":30}]}

Add New Entity:

---

Add a new Managed Entity class and use the generic SpecificationBuilder to perform the similar operations illustrated above.

For eg. Employee Entity - List the employees who are under Department#1

GET Method: http://localhost:8881/employees?dept=1