<dependencies>
<!-- springmvc的场景启动器 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.6.5</version>
</dependency>
<!-- MySQL驱动包 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.28</version>
</dependency>
<!-- Mybatis的场景启动器 -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.2</version>
</dependency>
<!-- 单元测试场景启动器 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>2.6.5</version>
</dependency>
</dependencies>
server:
#端口号
port: 9527
spring:
#数据库配置
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
username: root
password: 123456
# MyBatis配置
mybatis:
mapper-locations: com/thk/mapper/*Mapper.xml
public class People {
/**
* id
*/
private Long id;
/**
* 姓名
*/
private String name;
/**
* 年龄
*/
private Integer age;
/**
* 地址
*/
private String address;
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 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;
}
@Override
public String toString() {
return "People{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
", address='" + address + '\'' +
'}';
}
}
package com.thk.utils;
/**
* 分布式唯一ID 雪花算法实现
*/
public class SnowFlake {
/**
* 起始的时间戳
*/
private final static long START_TIMESTAMP = 1593446400L;
/**
* 每一部分占用的位数
*/
private final static long SEQUENCE_BIT = 12; //序列号占用的位数
private final static long MACHINE_BIT = 5; //机器标识占用的位数
private final static long DATA_CENTER_BIT = 5;//数据中心占用的位数
/**
* 每一部分的最大值
*/
private final static long MAX_DATA_CENTER_NUM = -1L ^ (-1L << DATA_CENTER_BIT);
private final static long MAX_MACHINE_NUM = -1L ^ (-1L << MACHINE_BIT);
private final static long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);
/**
* 每一部分向左的位移
*/
private final static long MACHINE_LEFT = SEQUENCE_BIT;
private final static long DATA_CENTER_LEFT = SEQUENCE_BIT + MACHINE_BIT;
private final static long TIMESTAMP_LEFT = DATA_CENTER_LEFT + DATA_CENTER_BIT;
/**
* 数据中心编码，初始化后不可修改
* 最大值: 2^5-1 取值范围: [0,31]
*/
private long dataCenterId;
/**
* 机器或进程编码，初始化后不可修改
* 最大值: 2^5-1 取值范围: [0,31]
*/
private long machineId;
/**
* 序列号
* 最大值: 2^12-1 取值范围: [0,4095]
*/
private long sequence = 0L;
private long lastStamp = -1L;//上一次时间戳
public SnowFlake(long dataCenterId, long machineId) {
if (dataCenterId > MAX_DATA_CENTER_NUM || dataCenterId < 0) {
throw new IllegalArgumentException("dataCenterId can't be greater than MAX_DATA_CENTER_NUM or less than 0");
}
if (machineId > MAX_MACHINE_NUM || machineId < 0) {
throw new IllegalArgumentException("machineId can't be greater than MAX_MACHINE_NUM or less than 0");
}
this.dataCenterId = dataCenterId;
this.machineId = machineId;
}
/**
* 产生下一个ID
*
* @return
*/
public synchronized long nextId() {
//获取当前时间戳 可用System.currentTimeMillis(); 方法替换
long currStamp = getNewStamp();
//保证当前时间戳不小于最后一次的时间戳
if (currStamp < lastStamp) {
throw new RuntimeException("Clock moved backwards. Refusing to generate id");
}
//如果当前时间戳等于最后一次时间戳 就进行序号递增
if (currStamp == lastStamp) {
//相同毫秒内，序列号自增
sequence = (sequence + 1) & MAX_SEQUENCE;
//同一毫秒的序列数已经达到最大
if (sequence == 0L) {
currStamp = getNextMill();
}
} else {
//不同毫秒内，序列号置为0
sequence = 0L;
}
//保存最后一次时间戳
lastStamp = currStamp;
//通过位运算，将相应的二进制数值放到对应的位置 41位时间戳 + 5位数据中心 + 5位机器码 + 12位序列号 ，首位没有使用
return (currStamp - START_TIMESTAMP) << TIMESTAMP_LEFT //时间戳部分
| dataCenterId << DATA_CENTER_LEFT //数据中心部分
| machineId << MACHINE_LEFT //机器标识部分
| sequence; //序列号部分
}
private long getNextMill() {
//获取当前时间戳
long mill = getNewStamp();
//获取大于上一次时间戳的时间戳
while (mill <= lastStamp) {
mill = getNewStamp();
}
return mill;
}
/**
* 获取当前时间戳
*/
private long getNewStamp() {
return System.currentTimeMillis();
}
}
package com.thk.controller;
import com.thk.domain.People;
import com.thk.service.IPeopleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import javax.websocket.server.PathParam;
import java.util.List;
@RestController
public class PeopleController {
@Autowired
private IPeopleService peopleService;
/**
* 查询全部用户
*
* @param people
* @return
*/
@GetMapping("/selectAll")
public List<People> selectAll(People people) {
return peopleService.selectAll(people);
}
/**
* 增加用户或者修改用户
*
* @param people
* @return
*/
@PostMapping("/people")
public int people(@RequestBody People people) throws Exception {
return peopleService.people(people);
}
/**
* 根据id查询一条数据
*
* @param id
* @return
*/
@GetMapping("/selectOne/{id}")
public People selectOne(@PathVariable Long id) {
return peopleService.selectOne(id);
}
/**
* 删除数据
* @param id
* @return
*/
@DeleteMapping("/delPeople/{id}")
public int delPeople(@PathVariable Long id) throws Exception{
return peopleService.delPeople(id);
}
}
public interface IPeopleService {
/**
* 查询全部用户
*
* @param people
* @return
*/
List<People> selectAll(People people);
/**
* 增加用户或者修改用户
*
* @param people
* @return
*/
int people(People people) throws Exception;
/**
* 根据id查询一条数据
*
* @param id
* @return
*/
People selectOne(Long id);
/**
* 删除数据
* @param id
* @return
*/
int delPeople(Long id) throws Exception;
}
@Service
public class PeopleImpl implements IPeopleService {
@Autowired
private PeopleMapper peopleMapper;
/**
* 查询全部用户
*
* @param people
* @return
*/
@Override
public List<People> selectAll(People people) {
return peopleMapper.selectAll(people);
}
/**
* 增加用户或者修改用户
*
* @param people
* @return
*/
@Override
public int people(People people) throws Exception {
//判断id是否为空，如果为空就是添加
if (StringUtils.isEmpty(people.getId())) {
SnowFlake snowFlake = new SnowFlake(2, 3);
long l = snowFlake.nextId();
//设置id
people.setId(l);
System.out.println("添加的id是" + l);
//添加数据
return peopleMapper.addPeople(people);
} else {
//如果id不为空，就是修改
//到数据库查询是否存在这条数据，如果不存在抛出异常
People people1 = peopleMapper.selectOne(people.getId());
if (people1 == null) {
throw new Exception("修改的数据不存在！！！");
}
//修改数据
return peopleMapper.updatePeople(people);
}
}
/**
* 根据id查询一条数据
*
* @param id
* @return
*/
@Override
public People selectOne(Long id) {
return peopleMapper.selectOne(id);
}
/**
* 删除数据
*
* @param id
* @return
*/
@Override
public int delPeople(Long id) throws Exception {
if (id != null) {
People people = peopleMapper.selectOne(id);
if (people != null) {
//删除数据
return peopleMapper.delPeople(id);
} else {
throw new Exception("修改的数据不存在！！！");
}
} else {
throw new Exception("数据异常！！！");
}
}
}
@Mapper
public interface PeopleMapper {
/**
* 查询全部用户
*
* @param people
* @return
*/
List<People> selectAll(People people);
/**
* 根据id查询一条数据
*
* @param id
* @return
*/
People selectOne(Long id);
/**
* 添加数据
*
* @param people
* @return
*/
int addPeople(People people);
/**
* 修改数据
*
* @param people
* @return
*/
int updatePeople(People people);
/**
* 删除数据
*
* @param id
* @return
*/
int delPeople(Long id);
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.thk.mapper.PeopleMapper">
<!--查询全部数据-->
<select id="selectAll" resultType="com.thk.domain.People">
SELECT * FROM people
</select>
<!--根据id查询一条数据-->
<select id="selectOne" resultType="com.thk.domain.People">
SELECT * FROM people where id =#{id}
</select>
<!--添加一条数据-->
<insert id="addPeople">
insert into people(id,name,age,address) values (#{id},#{name},#{age},#{address})
</insert>
<!--修改数据-->
<update id="updatePeople">
update people
<trim prefix="SET" suffixOverrides=",">
<if test="name != null and name != ''">name = #{name},</if>
<if test="age != null">age = #{age},</if>
<if test="address != null and address != ''">address = #{address},</if>
</trim>
where id = #{id}
</update>
<!--删除数据-->
<delete id="delPeople">
delete from
people
where id =#{id}
</delete>
</mapper>
启动程序：
运行结果：
运行结果：
查询全部数据，发现添加的数据已经被删除了
以上就是数据库单表额CRUD