Springboot2

1.使用maven构建项目

IDEA新建一个maven项目，创建好在pom.xml中添加依赖：

<?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.elite</groupId><artifactId>springboot-demo1</artifactId><version>1.0-SNAPSHOT</version><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.3.1.RELEASE</version></parent><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency></dependencies>
</project>

App启动类：

package com.elite.demo1;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;@SpringBootApplication
@RestController
public class App  {public static void main(String[] args) {SpringApplication.run(App.class,args);}//@GetMapping("/hello")public String hello(){return "hello,springboot!";}
}

访问结果如：

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快速入门的demo就完成了！

2.自动配置父类依赖

spring-boot-starter-parent 依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>2.3.1.RELEASE</version></parent><artifactId>spring-boot-starter-parent</artifactId><packaging>pom</packaging><name>spring-boot-starter-parent</name><description>Parent pom providing dependency and plugin management for applications built with Maven</description><build><resources><resource><directory>${basedir}/src/main/resources</directory><filtering>true</filtering><includes><include>**/application*.yml</include><include>**/application*.yaml</include><include>**/application*.properties</include></includes></resource><resource><directory>${basedir}/src/main/resources</directory><excludes><exclude>**/application*.yml</exclude><exclude>**/application*.yaml</exclude><exclude>**/application*.properties</exclude></excludes></resource></resources><pluginManagement><plugins><plugin><groupId>org.jetbrains.kotlin</groupId><artifactId>kotlin-maven-plugin</artifactId><version>${kotlin.version}</version><configuration><jvmTarget>${java.version}</jvmTarget><javaParameters>true</javaParameters></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><configuration><parameters>true</parameters></configuration></plugin><plugin>
</project>

配置文件位置

当前项目根目录下的config下
当前项目的根目录下
resources目录下的config目录下
resources目录下

注意：以上位置的优先级一次降低

配置文件方式

.xml文件方式
.yml方式

3.属性注入

1.spring注入的方式

application.properties

server.port=8081book.name=java
book.author=javaer
book.id=1

bookcontroller

package com.elite.demo1.controller;import com.elite.demo1.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class BookController {@AutowiredBook book;@GetMapping("/book")public Book book(){return book;}
}

访问：http://localhost:8081/book可以看到注入的属性值

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2.springboot的安全注入

book.name=springboot
book.author=javaer
book.id=2

book对象

package com.elite.demo1.domain;import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.stereotype.Component;@Component
@PropertySource("classpath:book.properties")
@ConfigurationProperties(prefix ="book")
public class Book {private Long id;private String name;private String author;//省略set get 方法
}

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3.yml注入

application.yml配置文件

my:servers:- dev.example.com- another.example.com

MyTestConfig对象

package com.elite.demo1.domain;import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;import java.util.ArrayList;
import java.util.List;@ConfigurationProperties(prefix = "my")
@Component
public class MyTestConfig {private List<String> servers = new ArrayList<>();public List<String> getServers() {return servers;}public void setServers(List<String> servers) {this.servers = servers;}
}

访问：

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4.自定义starter

1.建立自己properties类

package com.elite.starter;import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;@Component
@ConfigurationProperties(prefix="elite")
public class HelloProperties {//默认配置属性private static final String DEFAULT_NAME ="springboot";private static final String DEFAULT_MSG="javaer";private String name = DEFAULT_NAME;private String msg = DEFAULT_MSG;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getMsg() {return msg;}public void setMsg(String msg) {this.msg = msg;}
}

2.建立服务类

package com.elite.starter;public class HelloService {private String name;private  String msg;public String sayHello(){return name + " say " + msg + "!";}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getMsg() {return msg;}public void setMsg(String msg) {this.msg = msg;}
}

3.自动配置类

package com.elite.starter;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableMBeanExport;@Configuration
@EnableConfigurationProperties(HelloProperties.class)
@ConditionalOnClass(HelloService.class)
public class HelloServiceAutoConfiguration {@AutowiredHelloProperties helloProperties;@BeanHelloService helloService(){HelloService helloService = new HelloService();helloService.setName(helloProperties.getName());helloService.setMsg(helloProperties.getMsg());return helloService;}}

4.建立一个spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.elite.starter.HelloServiceAutoConfiguration

5.安装

使用maven install打包

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6.测试

1.添加自己的依赖

  <dependency><groupId>com.elite</groupId><artifactId>mystarter</artifactId><version>1.0-SNAPSHOT</version></dependency>

2.建立一个hellocontroller

package com.elite.demo1.controller;import com.elite.starter.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class HelloController {@AutowiredHelloService helloService;@RequestMapping("/sayhello")public String sayHello(){return helloService.sayHello();}
}

3.访问测试

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5.数据访问

1.jdbctemplate

新建一张user表**

create table user(id int not null primary key auto_increment,username varchar(20),age int,address varchar(255)
)engine=innodb;insert into user(username,age,address)values('a',12,'beijing');
insert into user (username,age,address)values('b',13,'shanghai');
insert into user (username,age,address)values('c',14,'shenzhen');

引入数据源druid以及mysql驱动

 <!--引入数据源druid依赖--><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.1.23</version></dependency><!--引入mysql驱动--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.49</version><scope>runtime</scope></dependency><!-- jdbc依赖 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency></dependencies>

配置数据库连接

server.port=8081
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8

查询结果1：

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新建一个用户实体类user

package com.elite.demo1.domain;public class User {private Integer id;private String username;private Integer age;private String address;//省略set get方法
}

userservice类

package com.elite.demo1.service;import com.elite.demo1.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.PreparedStatementCreator;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Service;import java.sql.*;
import java.util.List;@Service
public class UserService {@AutowiredJdbcTemplate jdbcTemplate;/*** 添加用户*/public int addUser(User user){KeyHolder keyHolder = new GeneratedKeyHolder();int update = jdbcTemplate.update(new PreparedStatementCreator() {@Overridepublic PreparedStatement createPreparedStatement(Connection connection) throws SQLException {PreparedStatement ps = connection.prepareStatement("insert into user " +"(username,age,address)values(?,?,?);", Statement.RETURN_GENERATED_KEYS);ps.setString(1,user.getUsername());ps.setInt(2,user.getAge());ps.setString(3,user.getAddress());return ps;}},keyHolder);user.setId((int) keyHolder.getKey().longValue());System.out.println(user);return update;}/*** 删除用户*/public int delUserById(Integer id){return jdbcTemplate.update("delete from user where id = ?",id);}/*** 更改*/public int updateUser(User user){return jdbcTemplate.update("update user set username=?,age = ? ,address=? where " +"id = ?",user.getUsername(),user.getAge(),user.getAddress(),user.getId());}/*** 查询用户**/public List<User> getAllUser(){return jdbcTemplate.query("select *from user", new RowMapper<User>() {@Overridepublic User mapRow(ResultSet resultSet, int i) throws SQLException {String username = resultSet.getString("username");Integer age = resultSet.getInt("age");String address = resultSet.getString("address");Integer id = resultSet.getInt("id");User user = new User();user.setId(id);user.setUsername(username);user.setAge(age);user.setAddress(address);return user;}});}/*** 查询2*/public List<User> getUserList(){return jdbcTemplate.query("select * from user",new BeanPropertyRowMapper<>(User.class));}
}

usercontroller类

package com.elite.demo1.controller;import com.elite.demo1.domain.User;
import com.elite.demo1.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;import javax.swing.*;
import java.util.List;@RestController
public class UserController {@AutowiredUserService userService;/*** 查询用户1* @return*/@GetMapping("getUserList1")public List<User> getUserList1(){return userService.getAllUser();}/*** 查询用户2* @return*/@GetMapping("getUserList2")public List<User> getUserList2(){return userService.getUserList();}/*** 删除用户* @param id* @return*/@RequestMapping("delUserById")public List<User> delUserById(@RequestParam("id") Integer id){int i = userService.delUserById(id);return   userService.getUserList();}/*** 增加用户* @param username* @param age* @param address* @return*/@RequestMapping("addUser")public List<User> delUserById(@RequestParam("username") String  username,@RequestParam("age") Integer age,@RequestParam("address") String address){User user = new User();user.setUsername(username);user.setAge(age);user.setAddress(address);userService.addUser(user);return   userService.getUserList();}@RequestMapping("updateUser")public List<User> updateUser(@RequestParam("id") Integer  id,@RequestParam("username") String  username,@RequestParam("age") Integer age,@RequestParam("address") String address){User user = new User();user.setId(id);user.setUsername(username);user.setAge(age);user.setAddress(address);userService.updateUser(user);return   userService.getUserList();}}

启动项目进行访问

查询结果2 http://localhost:8081/getUserList2[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-gRNK6zYn-1595723065877)(C:\Users\dell\AppData\Roaming\Typora\typora-user-images\image-20200725152859927.png)]

删除用户：http://localhost:8081/delUserById?id=3

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添加用户：http://localhost:8081/addUser?username=d&age=15&address=hangzhou[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-hiEdhpbU-1595723065881)(C:\Users\dell\AppData\Roaming\Typora\typora-user-images\image-20200725153222586.png)]

修改用户:http://localhost:8081/updateUser?id=1&username=aa&age=15&address=hangzhou

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2.mybatis

引入mybatis依赖

<dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.1.3</version></dependency>

基于mapper注解实现

package com.elite.demo1.mappers;import com.elite.demo1.domain.User;
import org.apache.ibatis.annotations.*;import java.util.List;public interface UserMapper {@Select("select * from user")List<User> getAllUsers();@Results({@Result(property = "id" ,column = "id"),@Result(property = "username",column = "u"),@Result(property = "age",column = "age"),@Result(property = "address",column = "a")})@Select("select id as id,username as u ,age as age,address as a from user where id=#{id}")User getUserByID(Integer id);/*** 按用户名模糊查询*/@Select("select * from user where username like concat('%',#{name},'%')")List<User> getUserByName(String name);/*** 插入用户*/@Insert({"insert into user(username,age,address)values(#{username},#{age},#{address})"})@SelectKey(statement = "select last_insert_id()",keyProperty = "id",before = false,resultType = Integer.class)Integer addUser(User user);/*** 更新用户*/@Update("update user set username=#{username},age=#{age},address=#{address} where id=#{id}")Integer updateUserById(User user);/*** 删除用户*/@Delete("delete from user where id=#{id}")Integer delUserById(Integer id);
}

UserMapperController

package com.elite.demo1.controller;import com.elite.demo1.domain.User;
import com.elite.demo1.mappers.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
import java.util.List;@RestController
public class UserMapperController {@ResourceUserMapper userMapper;/*** 查询用户通过id* @return*/@GetMapping("getUserList")public List<User> getUserList1(){return userMapper.getAllUsers();}/*** 通过id查询用户* @return*/@GetMapping("getUserById")public User getUserList2(@RequestParam("id") Integer id){return userMapper.getUserByID(id);}/*** 通过用户名模糊查询* @param name* @return*/@RequestMapping("getUserByName")public List<User> delUserById(@RequestParam("name") String name){return   userMapper.getUserByName(name);}/*** 增加用户* @param username* @param age* @param address* @return*/@RequestMapping("addUserByMapper")public List<User> delUserById(@RequestParam("username") String  username,@RequestParam("age") Integer age,@RequestParam("address") String address){User user = new User();user.setUsername(username);user.setAge(age);user.setAddress(address);userMapper.addUser(user);return   userMapper.getUserByName(username);}@RequestMapping("updateUserByMapper")public User updateUser(@RequestParam("id") Integer  id,@RequestParam("username") String  username,@RequestParam("age") Integer age,@RequestParam("address") String address){User user = new User();user.setId(id);user.setUsername(username);user.setAge(age);user.setAddress(address);userMapper.updateUserById(user);return   userMapper.getUserByID(id);}/*** 删除用户*//*** 通过id查询用户* @return*/@GetMapping("delUserByIdByMapper")public Integer delUserById(@RequestParam("id") Integer id){return userMapper.delUserById(id);}}

测试：修改用戶

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添加用戶

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查询用户

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刪除用戶

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基于xml配置

xml的位置放置问题:

 <build><resources><resource><directory>src/main/java</directory><includes>**/*.xml</includes></resource><resource><directory>src/main/resources</directory></resource></resources></build>

#mybatis的位置
mybatis.mapper-locations=classpath:mappers/UserMapper.xml

我这里是放在resource下：UserXmlMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.elite.demo1.mappers.UserXmlMapper"><select id="getUserById" parameterType="java.lang.Integer" resultType="com.elite.demo1.domain.User">select * from user where id=#{id}</select><select id="getUserList" resultType="com.elite.demo1.domain.User">select * from user</select><insert id="addUser" parameterType="com.elite.demo1.domain.User">insert into user(username,age,address)values (#{username},#{age},#{address})</insert><update id="updateUser" parameterType="com.elite.demo1.domain.User">update user set username=#{username},age = #{age},address = #{address}where id = #{id}</update><delete id="delUserById" parameterType="java.lang.Integer">delete from user where id=#{id}</delete>
</mapper>

还得书写一个接口类：

package com.elite.demo1.mappers;import com.elite.demo1.domain.User;import java.util.List;public interface UserXmlMapper {public User getUserById(Integer id);public List<User> getUserList();public void addUser(User user);public void updateUser(User user);public void delUserById(Integer id);}

需要注意：接口的名称和xml名称一致，接口方法名和xml的标签的id必须一致。

UserXmlMapperController类

package com.elite.demo1.controller;import com.elite.demo1.domain.User;
import com.elite.demo1.mappers.UserXmlMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
import java.util.List;@RestController
public class UserXmlMapperController {@ResourceUserXmlMapper userXmlMapper;/*** 查询用户*/@GetMapping("/getUserByXmlMapper")public User getUserByXmlMapper(@RequestParam("id") Integer id){return userXmlMapper.getUserById(id);}/*** 查询用户*/@GetMapping("/getUserListByXmlMapper")public List<User> getUserListByXmlMapper(){return userXmlMapper.getUserList();}/*** 增加用户* @param username* @param age* @param address* @return*/@GetMapping("addUserByXmlMapper")public List<User> addUserByXmlMapper(@RequestParam("username") String  username,@RequestParam("age") Integer age,@RequestParam("address") String address){User user = new User();user.setUsername(username);user.setAge(age);user.setAddress(address);userXmlMapper.addUser(user);return  userXmlMapper.getUserList() ;}@GetMapping("updateUserByXmlMapper")public User updateUser(@RequestParam("id") Integer  id,@RequestParam("username") String  username,@RequestParam("age") Integer age,@RequestParam("address") String address){User user = new User();user.setId(id);user.setUsername(username);user.setAge(age);user.setAddress(address);userXmlMapper.updateUser(user);return   userXmlMapper.getUserById(id);}/*** 删除用户*//*** 通过id查询用户* @return*/@GetMapping("delUserByIdByXmlMapper")public void delUserById(@RequestParam("id") Integer id){userXmlMapper.delUserById(id);}
}

测试：

查询用户：

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添加用户：

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修改用户

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删除用户：
(img-bAJb0Cz3-1595723065894)]