1、創建SpringBoot項目
兩種方式：1、通過idea來New一個project項目。
2、登陸 https://start.spring.io/ 上面選擇相應的配置，點擊“Generate Project”按鈕下載項目，完成項目初始化。
pom.xml文件的配置（其中mysql的maven配置可能會和你本地的不服，會報數據庫連接的錯誤，如果出現這種問題，改一下數據庫版本就可以）：
<?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> <groupId>com.example</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.1</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web-services</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <!--集成日志logback+slf4j --> <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.7.2</version> </dependency> </dependencies> <!--<packaging>jar</packaging>--> <build> <finalName>demo</finalName> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
application.properties文件中的配置項（端口、數據庫配置、debug、mybatis）
#項目的啟動端口 server.port=9090 #數據庫的配置 spring.datasource.url=jdbc:mysql://localhost:3306/DBName?useUnicode=true&characterEncoding=utf-8&useSSL=true spring.datasource.username= USERNAME spring.datasource.password= PASSWORD spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver #顯示標准輸出 logging.level.com.shyroke.mapper=debug #路徑是是實體類的路徑，和寫在所有Mapper文件中用來掃描Mapper文件的@Mapper注解聯用 mybatis.type-aliases-package=com.web.test.test.domain
2、項目內部結構
3、項目的最小功能代碼
這個例子是實現一個簡單的查詢功能：
Controller層：
package com.web.test.test.controller;
import com.web.test.test.service.TeacherService;
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 TeacherController {
@Autowired
private TeacherService teacherService;
//Select By Id
@RequestMapping("/showTeacher/{id}")
public String selectTeacher(@PathVariable int id){
return teacherService.selectTeacher(id).toString();
}
//Select All
@RequestMapping("/selectAll")
public String selectAll(){
return teacherService.selectAll().toString();
}
* 有的朋友想在return的時候直接跳轉界面去，看到@RestController了嗎，這個是ResponseBody和Controller的集合，意思是return的數據都變成json的格式，返回到前端，不會跳轉界面。
如果想跳轉頁面的話，就需要把RestController改成Controller，就會跳轉頁面了。
* 還有些朋友想帶着數據返回到重新定義的頁面去，對於這種需求，我建議使用“視圖解釋器解析”——ModelAndVIew。ModelAndView的用法類似於這樣：
@RequestMapping
public ModelAndView list(Model model) {
model.addAttribute("userList", userRepository.listUsers());
model.addAttribute("title", "用戶管理");
// new ModelAndView(目標頁面的路徑, 目標頁面接到的返回值名稱, api封裝好返回的數據)
return new ModelAndView("users/list","userModel",model);
}
Service層：
package com.we b.test.test.service;
import com.web.test.test.domain.Teacher;
import java.util.List;
public interface TeacherService {
Teacher selectTeacher(int id);
List<Teacher> selectAll();
}
Service層的實現類，在Service文件夾下的Impl文件夾中：
package com.test.test.Service.impl;
import com.test.test.Service.TeacherService;
import com.test.test.domain.Teacher;
import com.test.test.mapper.TeacherMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.List;
@Service
public class TeacherImpl implements TeacherService {
@Autowired
TeacherMapper mapper;
@Override
public Teacher selectTeacher(int id) {
return mapper.selectTeacher(id);
}
@Override
public List<Teacher> selectAll() {
return mapper.selectAll();
}
}
Mapper 相當於DAO層:
package com.we b.test.test.mapper;
import com.web.test.test.domain.Teacher;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import java.util.List;
@Mapper
public interface TeacherMapper {
@Select ("SELECT * FROM Teacher WHERE id = #{id}")
Teacher selectTeacher(int id);
@Select("SELECT * FROM TEACHER WHERE 1=1")
List<Teacher> selectAll();
}
Domain 實體類：
package com.web.test.test.domain;
public class Teacher {
private int id;
private String name;
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getId() {
return id;
}
@Override
public String toString() {
return "Teacher{" +"id=" + id +", name='" + name + '\'' +'}';
}
}
這樣就能實現@Select標簽的方式搭建SpringBoot的Mybatis框架了。挺簡單的，但是我不太喜歡用這種當時，Mybatis的繼承方式三種：@Select、@Provider、還有xml映射文件的方式。
@Select的方式寫得太死了，不夠靈活。更多的還是使用另外兩種方式。這兩天我會再介紹另外兩種方式。