springboot第一章09---集成Mybatis

操作步骤：

1.集成Mybatis

2.使用PageHelper分页

3.获取自增长id

第一步：添加依赖pom.xml

<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.fjz</groupId>
  <artifactId>spring-boot-demo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>spring-boot-demo</name>
  <url>http://maven.apache.org</url>

  
    <!-- spring-boot父节点依赖，相关的引入就不需要添加version配置，spring boot会选择最合适的版本进行添加  -->
	<parent>
		<groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-parent</artifactId>
	    <version>2.1.8.RELEASE</version>
	</parent>
 
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <!-- 指定jdk为1.8，默认为1.6 -->
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
  	<!-- 由于上面spring-boot-starter-parent已经指定了版本号，系统会自动选择合适的版本号，不需要再添加 -->
  	<dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-web</artifactId>
	</dependency>

	<!-- 添加fastjson依赖，用它来解析json数据，springboot默认的是Jackson解析json数据，但是这里我们自定义使用fastjson -->
	<dependency>
	    <groupId>com.alibaba</groupId>
	    <artifactId>fastjson</artifactId>
	    <version>1.2.62</version>
	</dependency>
	
	<!--devtools热部署-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
        <scope>true</scope>
    </dependency>
        
    <!-- 添加Mysql数据库驱动依赖 -->
   <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
   </dependency>

	<!-- mybatis依赖 -->
	<dependency>
	    <groupId>org.mybatis.spring.boot</groupId>
	    <artifactId>mybatis-spring-boot-starter</artifactId>
	    <version>2.1.1</version>
	</dependency>
	
	<!-- pagehelper依赖 -->
	<dependency>
	    <groupId>com.github.pagehelper</groupId>
	    <artifactId>pagehelper-spring-boot-starter</artifactId>
	    <version>1.2.5</version>
	</dependency>
	
   <!-- 添加Spring-boot-starter-data-jpa依赖 -->
   <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
   </dependency>
    
    <!-- 添加thymeleaf的依赖 -->
    <dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-thymeleaf</artifactId>
	</dependency>
    
    <!-- 添加freemarker的依赖 -->
    <dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-freemarker</artifactId>
	</dependency>
    
    <!-- servlet依赖 -->
	<dependency>
	    <groupId>javax.servlet</groupId>
	    <artifactId>javax.servlet-api</artifactId>
	    <scope>provided</scope>
	</dependency>
	
	<!-- jstl 依赖-->
	<dependency>
	    <groupId>javax.servlet</groupId>
	    <artifactId>jstl</artifactId>
	</dependency>
	
	<!--tomcat依赖 -->
	<dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-tomcat</artifactId>
	</dependency>
    
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  
  <!-- 构建节点 -->
  <build>
  	<plugins>
  		<plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                </configuration>
            </plugin>
 
  	</plugins>
  </build>
  
</project>

第二步：编写MybatisConfiguration.java(分页用)

package com.fjz.config;

import java.util.Properties;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.github.pagehelper.PageHelper;


@Configuration
public class MybatisConfiguration {

	@Bean
	public PageHelper pageHelper(){
		System.out.println("你好");
		PageHelper pageHelper = new PageHelper();
		Properties pro = new Properties();
		pro.setProperty("offsetAsPageNum", "true");
		pro.setProperty("rowBoundsWithCount", "true");
		pro.setProperty("reasonable", "true");
		pageHelper.setProperties(pro);
		return pageHelper;
	}
}

 第三步：编写一个实体类：user.java

package com.fjz.user.bean;

import java.io.Serializable;

public class User implements Serializable{

	private long id;
	private String name;
	
	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;
	}
	
	
}

第四步：编写UserMapper.java

package com.fjz.user.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Select;

import com.fjz.user.bean.User;

public interface UserMapper {

	/**
	 * 模糊查询
	 * @param name
	 * @return
	 */
	@Select("select * from user where name = #{name}")
	public List<User> likeName(String name);
	
	/**
	 * 根据id查询
	 * @param id
	 * @return
	 */
	@Select("select * from user where id = #{id}")
	public User selectById(long id);
	
	/**
	 * 根据id查询name
	 * @param id
	 * @return
	 */
	@Select("select name from user where id = #{id}")
	public String selectNameById(long id);
}

第五步：编写UserService.java

package com.fjz.user.service;


import com.fjz.user.bean.User;
import com.fjz.user.mapper.UserMapper;
import com.github.pagehelper.PageHelper;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserService {

	@Autowired
	private UserMapper userMapper;
	
	/**
	 * 模糊查询
	 * @param name
	 * @return
	 */
	public List<User> likeName(String name){
		
		return userMapper.likeName(name);
	}
}

第六步：编写UserController.java

package com.fjz.user.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;

import com.fjz.user.bean.User;
import com.fjz.user.service.UserService;
import com.github.pagehelper.PageHelper;

import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {

	@Autowired
	private UserService userService;
	
	/**
	 * 模糊查询
	 * @param name
	 * @return
	 */
	@RequestMapping("/likeName")
	public List<User> likeName(String name){
		//第一页，显示两条数据
		PageHelper.startPage(1, 2);
		return userService.likeName(name);
	}
}

 第七步：编写启动类App.java，并启动

注：这里的注解@MapperScan("com.fjz.*.mapper")需要注意

package com.fjz;

import java.util.ArrayList;
import java.util.List;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.context.annotation.Bean;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;

import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;

/**
 * 用@SpringBootApplication指定这是springboot的启动程序
 * @author fengjinzhu
 *
 */
@SpringBootApplication

//扫描该包下的class,主要是Mybatis 的持久化类
//如果不可以的话，可以将包扩展为com.fjz.*
@MapperScan("com.fjz.*.mapper")
public class App {
	
    public static void main( String[] args ) {
        SpringApplication.run(App.class, args);
    }
}

第八步：测试

===============此部分为id自增长 ==============

UserMapper.java

/**
     * 添加
     * @param user
     */
    @Insert("insert into user(name) values(#{name})")
    public void save(User user);

UserService.java

@Transactional
    public void save(User user){
        userMapper.save(user);
    }

UserController.java

/**
     * 添加信息
     * @return
     */
    @RequestMapping("/save")
    public User save(){
        User user = new User();
        user.setName("张三");
        userService.save(user);
        return user;
    }

测试：

但是数据库中却显示：

比较得知：两张图的id不同

那么怎么解决？

只需要在UserMappe.java中加上注解@Options即可

 /**
     * 添加
     * @param user
     */
    @Insert("insert into user(name) values(#{name})")
    @Options(useGeneratedKeys =true, keyProperty = "id", keyColumn = "id")
    public void save(User user);

测试得到：id与数据库保持一致