Spring Boot 学习研究笔记(七) -使用SpringData JPA访问PostgreSql数据库

<dependency>
    <groupId>org.postgresql</groupId>
     <artifactId>postgresql</artifactId>
     <scope>runtime</scope>
</dependency>

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://127.0.0.1:5432/test
spring.datasource.username=postgres
spring.datasource.password=123456
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

package com.example.demo;
import javax.persistence.*;
import java.io.Serializable;
/**
 * @DESC users表的实体类
 * @author guchuang
 */
@Entity
@Table(name="users")
public class User implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "menuSeq")
    @SequenceGenerator(name = "menuSeq", initialValue = 100000, allocationSize = 1, sequenceName = "MENU_SEQUENCE")
    @Column(name="id")//数据库字段名
    private int id;
    private int age;
    private String name;
    public User() {
    }
    public User(int id, int age, String name) {
        this.id = id;
        this.age = age;
        this.name = name;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", age=" + age + ", name=" + name + "]";
    }
}

/**
 * @DESC 实现jpa接口，拥有jpa提供的默认crud操作，无需自己写实现代码（除非要扩展功能）
 * @author guchuang
 *
 */
public interface UserRepository extends JpaRepository<User,Integer> {
}

package com.example.demo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.*;
import java.sql.SQLException;
import java.util.List;
import java.util.Optional;
@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;
    public List<User> getUser() throws SQLException {
        System.out.println("userRepository: " + userRepository);
        List<User> users = userRepository.findAll();
        return users;
    }
    public User getUser(@PathVariable(value="id") int id) throws SQLException {
        Optional<User> user = userRepository.findById(id);
        return user.get();
    }
    public String saveUser(@RequestBody User user){
        userRepository.save(user);
        return "success to add user";
    }
    public String updateUser(@RequestBody User user){
        userRepository.deleteById(user.getId());
        userRepository.save(user);
        return "success to update user";
    }
    public String deleteUser(@PathVariable(value="id") int id){
        userRepository.deleteById(id);
        return "success to delete user";
    }
}

package com.example.demo;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.sql.SQLException;
import java.util.List;
import java.util.Optional;
@Api(value = "JPA 用户操作")
@RestController
@RequestMapping("/jpa")
public class JpaUserController {
    @Autowired
    private UserService userService;
    @ApiOperation(value = "初始化", notes = "/init")
    @GetMapping("/init")
    public void  init() {
        for (int id =1000;id<1010;id++)
        {
            User u = new User();
            u.setName("name"+id);
            u.setAge(id % 10);
            saveUser(u);
        }
    }
    @ApiOperation(value = "获取用户列表", notes = "/list")
    @GetMapping("/list")
    public List<User> getUser() throws SQLException {
        return userService.getUser();
    }
    @ApiOperation(value = "获取用户", notes = "/user")
    @GetMapping("/user")
    public User getUser(@ApiParam(value = "获取单个用户", required = true) @RequestParam int id)  throws SQLException {
        return userService.getUser(id);
    }
    @ApiOperation(value = "保存用户", notes = "/user")
    @PostMapping(value = "/user")
    public String saveUser(@RequestBody User user){
        return userService.saveUser(user);
    }
    @PutMapping(value = "/user")
    public String updateUser(@RequestBody User user){
        return  userService.updateUser(user);
    }
    @DeleteMapping(value = "/user/{id}")
    public String deleteUser(@PathVariable(value="id") int id){
        return userService.deleteUser(id);
    }
}