从零构建一个JAVA(SpringBoot)项目
1.创建一个Maven项目
1.1打开IDEA，点击创建项目
1.2 编写Hello World测试项目是否构建成功
1.3 修改Maven本地仓库地址
1.4 把项目提交到码云
- 选择本地仓库
- 提交（commit）到本地仓库
1.5 推送到远程仓库
- 快捷键：Ctrl+Shift+K
- 复制远程新建的仓库连接并粘贴
- OK后的状态，点击push即可上传到远程仓库
问题：
1.Push rejected Push to origin/master was rejected
大概原因是：初始化项目时，远程仓库我建了README.md文件，而本地仓库与远程仓库尚未进行文件关联，因此需要将两个仓库的文件进行关联后提交。
1.切换到自己项目所在的目录，右键选择GIT BASH Here，Idea中可使用Alt+F12
2.在terminl窗口中依次输入命令：
git pull
git pull origin master
git pull origin master --allow-unrelated-histories
3.在idea中重新push自己的项目
git push -u origin master -f
2.Git 中 出现couldn’t find remote ref –allow-unrelated-histories的解决办法
当执行git中的“git pull origin master –allow-unrelated-histories”命令时，会出现“ couldn’t find remote ref –allow-unrelated-histories”的错误，输入如下命令即可解决：
git pull --rebase origin master
git push origin maste
2.构建SpringBoot项目架构
2.1创建数据库
- 创建表
也可以通过sql创建表，添加字段信息，可以按F6切换到sql界面
2.2创建SpringBoot脚手架
- 配置SpringBoot依赖，编写pom文件
<?xml version="1.0" encoding="UTF-8"?>
<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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.1.RELEASE</version>
</parent>
<groupId>org.xph</groupId>
<artifactId>profile</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<!-- web-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- mysql数据库驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.17</version>
</dependency>
<!-- 数据库连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.2.3</version>
</dependency>
<!-- fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.75</version>
</dependency>
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>5.5.8</version>
</dependency>
</dependencies>
</project>
- 编写Springboot启动类：
-
编写测试Controller类
package com.xph.demo; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class demoController { @RequestMapping("/hello") public String hello() { return "Hello World"; } }@RestController
@RestController = @Controller + @ResponseBody组成，等号右边两位同志简单介绍两句，就明白我们@RestController的意义了：
- @Controller 将当前修饰的类注入SpringBoot IOC容器，使得从该类所在的项目跑起来的过程中，这个类就被实例化。当然也有语义化的作用，即代表该类是充当Controller的作用
- @ResponseBody 它的作用简短截说就是指该类中所有的API接口返回的数据，甭管你对应的方法返回Map或是其他Object，它会以Json字符串的形式返回给客户端，本人尝试了一下，如果返回的是String类型，则仍然是String
@RequestMapping
作用：将请求和处理请求的控制器方法关联起来，建立映射关系。
位置：
1、标识类：设置映射请求的请求路径的初试信息
2、表示方法：设置映射请求的请求路径的具体信息 -
输入http://localhost:8080/hello，测试
2.3 SpringBoot连接MYSQL数据库
-
添加mybatis-plus依赖
<!-- mybatis-plus--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.4.2</version> </dependency> -
添加完，完整的pom.xml文件如下
<?xml version="1.0" encoding="UTF-8"?> <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> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.3.1.RELEASE</version> </parent> <groupId>org.xph</groupId> <artifactId>profile</artifactId> <version>1.0-SNAPSHOT</version> <properties> <maven.compiler.source>8</maven.compiler.source> <maven.compiler.target>8</maven.compiler.target> </properties> <dependencies> <!-- web--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- mysql数据库驱动--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.17</version> </dependency> <!-- 数据库连接池--> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.2.3</version> </dependency> <!-- fastjson--> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.75</version> </dependency> <!-- hutool-all--> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>5.5.8</version> </dependency> <!-- mybatis-plus--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.4.2</version> </dependency> </dependencies> </project> -
配置数据库相关设置
spring: datasource: driver-class-name: com.mysql.jdbc.Driver username: root password: root url: jdbc:mysql://localhost:3306/person_profile?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8 mybatis-plus: mapper-locations: classpath*:/mapper/**/*.xml configuration: map-underscore-to-camel-case: true cache-enabled: true lazy-loading-enabled: true multiple-result-sets-enabled: true log-impl: org.apache.ibatis.logging.nologging.NoLoggingImpl global-config: db-config: id-type: assign_id table-underline: true banner: false enable-sql-runner: true configuration-properties: prefix: blobType: BLOB boolValue: true2.4建立规范化的SpringBoot模块
- 编写数据库实体类
package com.xph.moduler.demo.pojo;
import com.baomidou.mybatisplus.annotation.TableName;
import java.security.PrivateKey;
import java.sql.PreparedStatement;
@TableName("student")
public class Student {
/*
* 姓名
* */
private String name;
/*
* 年龄
* */
private Integer age;
/*
* 编号
* */
private Integer 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 Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
}
- 编写Mapper
package com.xph.moduler.demo.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.xph.moduler.demo.pojo.Student;
@Mapper
public interface StudentMapper extends BaseMapper<Student> {
}
- 编写Service
package com.xph.moduler.demo.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.xph.moduler.demo.pojo.Student;
public interface StudentService extends IService<Student> {
}
- 编写ServiceImpl
package com.xph.moduler.demo.service.impl;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.xph.moduler.demo.mapper.StudentMapper;
import com.xph.moduler.demo.pojo.Student;
import com.xph.moduler.demo.service.StudentService;
import org.springframework.stereotype.Service;
@Service
public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student> implements StudentService {
}
-
编写Controller
package com.xph.moduler.demo.controller; import com.xph.moduler.demo.pojo.Student; import com.xph.moduler.demo.service.StudentService; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import javax.annotation.Resource; import java.util.List; @RestController public class demoController { @Resource private StudentService studentService; @RequestMapping("/student") public List<Student> getStudentList() { return studentService.list(); } @RequestMapping("/hello") public String hello() { return "Hello World"; } } -
输入http://localhost:8080/student
import java.util.List;
@RestController
public class demoController {
@Resource
private StudentService studentService;
@RequestMapping("/student")
public List<Student> getStudentList() {
return studentService.list();
}
@RequestMapping("/hello")
public String hello() {
return "Hello World";
}
}