基于SSM和Spring Boot框架技术的手机POS前置平台应用，首先需要创建一个Spring Boot项目，并添加相关依赖。以下是一个简单的pom.xml文件配置：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.example</groupId>
  <artifactId>mobile-pos</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>mobile-pos</name>
  <url>http://maven.apache.org</url>

  <properties>
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <scope>runtime</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
</project>

接下来，创建一个实体类，例如Order,用于表示订单信息：

package com.example.mobilepos;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Order {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;
  private String orderNo;
  private double amount;
  // 其他属性和getter、setter方法省略
}

然后，创建一个OrderRepository接口，继承JpaRepository,用于操作数据库：

package com.example.mobilepos;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.example.mobilepos.entity.Order;
import java.util.List;
import java.util.Optional;

@Repository
public interface OrderRepository extends JpaRepository<Order, Long> {
  Optional<Order> findByOrderNo(String orderNo);
}

接下来，创建一个OrderService类，用于处理订单相关的业务逻辑：

package com.example.mobilepos;
import com.example.mobilepos.entity.Order;
import com.example.mobilepos.repository.OrderRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.Optional;
import java.util.List;
import java.util.stream.Collectors;
@Service
public class OrderService {
  @Autowired
  private OrderRepository orderRepository;

  public List<Order> getAllOrders() {
    return orderRepository.findAll();
  }
}

然后，创建一个OrderController类，用于处理HTTP请求：

package com.example.mobilepos;
import com.example.mobilepos.entity.Order;
import com.example.mobilepos.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import static org.springframework.web.bind.annotation.RequestMapping$.method;