六角鼠年鐵人賽 Week 30 - Spring Boot - Spring Data & JPA Paging 範例

大家好，我是 "為了拿到金角獎盃而努力著" 的文毅青年 - Kai

Marc Jacobs

You can never please everyone, and I think it's best not to.

主題

這篇就來分享實作分頁功能的範例，同樣會利用到之前建構的資料與程式。

Kai 這邊新增一個 Controller，並在原先的 EmployeeRepository.java 中增加一個會用到的分頁方法。

透過 Pageable 物件設定頁、顯示筆數、排序依據，一次設定好所有分頁功能需要用到的參數，並將 Pageable 物件放入 Repository 的方法當中，Spring Data JPA 的套件會自動在 SQL 中生成相對應的分頁 SQL 語法後執行，並帶出最終結果，不需要開發者再去設定過多的處理。

JPAPagingController.java










































package kai.com.jpa.controller;

import kai.com.jpa.entity.Employee;
import kai.com.jpa.repository.EmployeeRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.web.bind.annotation.*;

import java.sql.Date;
import java.util.List;

@RestController
@RequestMapping("/getEmpPaging")
public class JPAPagingTestController {

    @Autowired
    EmployeeRepository employeeRepository;

    @GetMapping("/build")
    public String buildTableAndData(){

        /*** 建立測試資料 ***/
        for(int i = 0; i < 20;i++) {
            Employee emp = new Employee();
            emp.setEmp_name("Tester_"+i);
            emp.setEmp_team("IT");
            emp.setEmp_birthDate(new Date(19920101));
            employeeRepository.save(emp);
        }
        return "Done build.";
    }

    @GetMapping("/{page}/{rows}")
    public List<Employee> getAllByIDPaging(@PathVariable("page") int page, @PathVariable("rows") int rows){

        Pageable pageable = PageRequest.of(page, rows, Sort.by("id"));
        return employeeRepository.findByIDPaging(pageable);
    }

}

EmployeeRepository.java



















package kai.com.jpa.repository;

import kai.com.jpa.entity.Employee;
import kai.com.jpa.entity.Employee2;
import kai.com.jpa.entity.QEmployee;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.querydsl.QuerydslPredicateExecutor;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;

import java.util.List;
import java.util.Optional;

public interface EmployeeRepository extends CrudRepository<Employee, Long>{

    @Query("FROM Employee as e")
    public List<Employee> findByIDPaging(Pageable pageable);
}

Employee.java



































































package kai.com.jpa.entity;

import javax.persistence.*;
import java.sql.Date;



/*
@NamedNativeQueries({
        @NamedNativeQuery(
                name = "Employee.findByPriorityExclude",
                query = "SELECT * FROM Employee as e WHERE e.emp_id <> ?1",
                resultClass=Employee.class
        )
})
*/
@Entity
public class Employee {

    public Employee (){}

    public Employee(String name, String team, Date birthDate){
        this.emp_name = name;
        this.emp_team = team;
        this.emp_birthDate = birthDate;
    }

    @Id
    @GeneratedValue(strategy= GenerationType.AUTO)
    private Long emp_id;

    private String emp_name;
    private String emp_team;
    private Date emp_birthDate;

    public Long getEmp_id() {
        return emp_id;
    }

    public void setEmp_id(Long emp_id) {
        this.emp_id = emp_id;
    }

    public String getEmp_name() {
        return emp_name;
    }

    public void setEmp_name(String emp_name) {
        this.emp_name = emp_name;
    }

    public String getEmp_team() {
        return emp_team;
    }

    public void setEmp_team(String emp_team) {
        this.emp_team = emp_team;
    }

    public Date getEmp_birthDate() {
        return emp_birthDate;
    }

    public void setEmp_birthDate(Date emp_birthdate) {
        this.emp_birthDate = emp_birthdate;
    }
}