收到短信说备案被退回但工信部网站上正常啊楚雄今日头条新闻
今天学习的是Restful实战
Dao层的完成
通过前面的学习，我们知道Dao 是直接面向数据库的，所以我们配好数据库环境。
创建一个名为restful_crud的数据库
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;-- ----------------------------
-- Table structure for employee
-- ----------------------------
DROP TABLE IF EXISTS `employee`;
CREATE TABLE `employee` (`id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键',`name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '员工名字',`age` int NULL DEFAULT NULL COMMENT '年龄',`email` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '邮箱',`gender` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '性别',`address` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '住址',`salary` decimal(10, 2) NULL DEFAULT NULL COMMENT '薪资',PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;-- ----------------------------
-- Records of employee
-- ----------------------------
INSERT INTO `employee` VALUES (1, '张三', 11, 'aa@qq.com', '男', '西安', 9999.00);
INSERT INTO `employee` VALUES (4, 'leifengyang', 10, 'aaa', '男', 'sss', 100.00);SET FOREIGN_KEY_CHECKS = 1;
然后在application.properities配置数据库信息
spring.application.name=springmvc-restful-crud
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/restful_crud
spring.datasource.username=root
spring.datasource.password=123456
Employee
package com.atguigu.rest.crud.bean;import lombok.Data;import java.math.BigDecimal;public class Employee {private Long id;private String name;private Integer age;private String email;private String gender;private String address;private BigDecimal salary;@Overridepublic String toString() {return "Employee{" +"address='" + address + '\'' +", id=" + id +", name='" + name + '\'' +", age=" + age +", email='" + email + '\'' +", gender='" + gender + '\'' +", salary=" + salary +'}';}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getGender() {return gender;}public void setGender(String gender) {this.gender = gender;}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public BigDecimal getSalary() {return salary;}public void setSalary(BigDecimal salary) {this.salary = salary;}
}在controller文件夹下创建EmployeeDao接口
package com.atguigu.rest.crud.dao;import com.atguigu.rest.crud.bean.Employee;public interface EmployeeDao {Employee getEmployeeById(Long id);void addEmployee(Employee employee);void updateEmployee(Employee employee);void deleteEmployee(Long id);
}在controller/impl创建EmployeeDaoImpl实现类
需要补充的点
BeanPropertyRowMapper 是 Spring JDBC 框架中的一个实用类，用于将数据库查询结果集（ResultSet）自动映射到 Java Bean 对象。它通过反射机制，根据列名与 Bean 属性名的匹配关系进行自动映射，大大简化了手动从结果集提取数据并赋值给对象的过程。
package com.atguigu.rest.crud.dao.impl;import com.atguigu.rest.crud.bean.Employee;
import com.atguigu.rest.crud.dao.EmployeeDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;@Component
public class EmployeeDaoImpl implements EmployeeDao {@Autowiredprivate JdbcTemplate jdbcTemplate;@Overridepublic Employee getEmployeeById(Long id) {String sql = "select * from employee where id = ?";Employee employee = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(Employee.class), id);return employee;}@Overridepublic void addEmployee(Employee employee) {String sql = "insert into employee (name, age , email,gender,address,salary) values (?, ? , ? , ? , ? , ?)";int update = jdbcTemplate.update(sql, employee.getName(), employee.getAge(), employee.getEmail(), employee.getGender(), employee.getAddress(), employee.getSalary());System.out.println("新增成功，影响行数" + update);}@Overridepublic void updateEmployee(Employee employee) {String sql = "update employee set name=?,age=?,email=?,gender=?,address=?,salary=? where id = ?";int update = jdbcTemplate.update(sql , employee.getName(), employee.getAge(), employee.getEmail(), employee.getGender(), employee.getAddress(), employee.getSalary(), employee.getId());System.out.println("新增成功，影响行数" + update);}@Overridepublic void deleteEmployee(Long id) {String sql = "delete from employee where id = ?";int update = jdbcTemplate.update(sql, id);}
}Service层的完成
需要注意到的一点就是，Dao层的update操作中，如果某些参数为空的时候，会出现修改后仍为空的情况，作为controller直接调用的层，可以对数据做预处理。
代码
/service/impl/EmployeeService
package com.atguigu.rest.crud.service;import com.atguigu.rest.crud.bean.Employee;public interface EmployeeService {Employee getEmp(Long id);void updateEmp(Employee employee);void addEmp(Employee employee);void deleteEmp(Long id);
}/service/impl/EmployeeServiceImpl
StringUtils可以判断 字符是否非空非空白，如果是，则返回true
package com.atguigu.rest.crud.service.impl;import ch.qos.logback.core.util.StringUtil;
import com.atguigu.rest.crud.bean.Employee;
import com.atguigu.rest.crud.dao.EmployeeDao;
import com.atguigu.rest.crud.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;@Service //controller 调用 service
public class EmployeeServiceImpl implements EmployeeService {@Autowiredprivate EmployeeDao employeeDao;//静态代理@Overridepublic Employee getEmp(Long id) {Employee empById = employeeDao.getEmployeeById(id);return null;}@Overridepublic void updateEmp(Employee employee) {//防null 处理。考虑到service是被controller调用的//controller层传过来的employee的某些属性可能为null,所以先处理一下// 先查一下找原始数据// 把页面带来的数据覆盖原有的值Long id = employee.getId();if(id == null) return ;//没有带idSystem.out.println(id);Employee empById = employeeDao.getEmployeeById(id);//StringUtils可以判断 字符是否非空非空白if(!StringUtils.hasText(employee.getAddress())){empById.setAddress(employee.getAddress());}if(!StringUtils.hasText(employee.getName())){empById.setName(employee.getName());}if(!StringUtils.hasText(employee.getGender())){empById.setGender(employee.getGender());}if(!StringUtils.hasText(employee.getEmail())){empById.setEmail(employee.getEmail());}if(!StringUtils.hasText(employee.getName())){empById.setName(employee.getName());}if(employee.getSalary() != null){empById.setSalary(employee.getSalary());}if(employee.getAge() != null){empById.setAge(employee.getAge());}employeeDao.updateEmployee(employee);}@Overridepublic void addEmp(Employee employee) {employeeDao.addEmployee(employee);}@Overridepublic void deleteEmp(Long id) {employeeDao.deleteEmployee(id);}
}Controller层的完成
设计目标
路径变量 PathVariable
我们可以在路径上定义一个动态变量接收一个参数，比如"/employee/{id}"
get方法的编写如下，相对于之前学习的@RequestParam，这里用到了@PathVariable去接收路径上的参数信息。
package com.atguigu.rest.crud.controller;import com.atguigu.rest.crud.bean.Employee;
import com.atguigu.rest.crud.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class EmployeeRestController {@Autowiredprivate EmployeeService employeeService;@RequestMapping("/employee/{id}")//路径变量，动态的,{id}可以随机取值public Employee get(@PathVariable Long id) {//PathVariable路径变量，因为路径是动态的Employee employee = employeeService.getEmp(id);System.out.println(employee);return employee;}
}crud的实现全代码
package com.atguigu.rest.crud.controller;import com.atguigu.rest.crud.bean.Employee;
import com.atguigu.rest.crud.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;@RestController
public class EmployeeRestController {@Autowiredprivate EmployeeService employeeService;@RequestMapping(value = "/employee/{id}" , method = RequestMethod.GET)//路径变量，动态的,{id}可以随机取值public Employee get(@PathVariable Long id) {//PathVariable路径变量，因为路径是动态的Employee employee = employeeService.getEmp(id);System.out.println(employee);return employee;}@RequestMapping(value = "/employee/{id}" , method = RequestMethod.DELETE)//路径变量，动态的,{id}可以随机取值public String delete(@PathVariable("id") Long id) {//PathVariable路径变量，因为路径是动态的employeeService.deleteEmp(id);return "ok";}@PostMapping("/employee")public String add(@RequestBody Employee employee) {employeeService.addEmp(employee);return "ok";}@PutMapping("/employee")public String update(@RequestBody Employee employee) {//必须携带idemployeeService.updateEmp(employee);return "ok";}
}崩溃ing，找错误找半天，最终才发现是因为定义R类的时候没加getter方法，是因为我在用@Data的时候，总是爆神秘错误，然后我就手动getter and setter了，但是没加getter，可能是因为没getter获取不到里面的数据吧，然后就无法转换成功，呜呜呜。
不过查询相关资料，好像有个神秘的解决该错误的方法
神秘方法，然后用这个方法确实成功解决了问题。
在pom.xml注释掉该段，加上刷新一下maven即可。
class类R的编写
package com.atguigu.rest.crud.common;import lombok.Data;@Data
public class R<T> {private Integer code;private String msg;private T data;public static <T> R<T> ok(T data) {R<T> r = new R<>();r.setCode(200);r.setMsg("ok");r.setData(data);return r;}public static <T> R<T> ok() {R<T> r = new R<>();r.setCode(200);r.setMsg("ok");return r;}
}查询所有员工的实现
EmployeeImpl的实现，用的是query接口
@Overridepublic List<Employee> getList() {String sql = "select * from employee";List<Employee> list = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Employee.class));return list;}