[JAVA] A memorandum when creating a REST service with Spring Boot

Overview

I will keep a memorandum when using REST services on Spring Web using STS. Mainly for myself. Spring Web is based on Spring Framework A web application framework.

The development environment is as follows. OS : Windows 7 Home Edition 64bit Java : JavaSE 8 update 181 Spring Boot : 2.3.4 STS : 4.6.1

STS setup

For the STS setup, I referred to My memorandum.

Creating a project

Create a project with Create new Spring Starter Project, The referenced libraries are as follows.

• Spring Web
• Spring Data JPA
• Oracle Driver
• Lombok

Creating an application

The created class, configuration file, and prepared data are as follows.

Spring Boot Execution class when the application starts.

SpringWebSampleApplication.java

package jp.co.illmatics;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringWebSampleApplication {

	public static void main(String[] args) {
		SpringApplication.run(SpringWebSampleApplication.class, args);
	}

}

This class is a REST API.

@RestController to make it a REST API, CORS @CrossOrigin to grant access Each was given.

The value that can be obtained is in JSON format. Details of the values will be explained later.

UsersController.java

package jp.co.illmatics.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import jp.co.illmatics.dao.UserDao;
import jp.co.illmatics.model.User;

@CrossOrigin
@RestController
public class UsersController {

	@Autowired
	private UserDao userInfoDao;

	@RequestMapping(method = RequestMethod.GET, value = "/users")
	public List<User> get() {
		return userInfoDao.getUserInfoList();
	}
}

Data Access Object. Both the interface and its implementation classes are required at the time of implementation.

UserDao.java

package jp.co.illmatics.dao;

import java.util.List;

import jp.co.illmatics.model.User;

public interface UserDao {

	public List<User> getUserInfoList();
}

UserDao implementation class. Defines a method to get a list of Users. ID column All items are acquired in ascending order.

UserDaoImpl.java

package jp.co.illmatics.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;

import jp.co.illmatics.model.User;

@Repository
public class UserDaoImpl implements UserDao {

	@Autowired
	private JdbcTemplate jdbcTemplate;

	public List<User> getUserInfoList() {
		List<User> list = jdbcTemplate.query("select * from USER_INFO ORDER BY ID"
			, new Object[] {},
			new RowMapper<User>() {
				public User mapRow(ResultSet rs, int rowNum) throws SQLException {
					User user = new User();
					user.setId(rs.getString("ID"));
					user.setName(rs.getString("NAME"));
					user.setAge(rs.getInt("AGE"));
					return user;
				}
			});
		return list;
	}
}

The model class for the USER_INFO table.

User.java

package jp.co.illmatics.model;

import javax.persistence.Table;

import org.springframework.stereotype.Component;

import lombok.Data;

@Data
@Component
@Table(name = "USER_INFO")
public class User {

	private String id;

	private String name;
	
	private Integer age;

}

DB connection information that stores test data.

application.properties

spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:XE
spring.datasource.username=xxxxxx
spring.datasource.password=xxxxxx
spring.jpa.database-platform=org.hibernate.dialect.Oracle10gDialect
spring.jpa.show-sql=true

This is the created table.

• The table name USER cannot be created because it is a reserved word. It has a name like this.

Created table

create table USER_INFO (
  "ID" varchar2(20), 
  "NAME" varchar2(20), 
  "AGE" number(3,0), 
  constraint "PK_USER" primary key ("ID")
);

This is the data prepared in the USER_INFO table.

Operation check

I will try it. It's done.

that's all. Until the end Thank you for reading.