idea 整合springboot mybatis jsp案例

spring boot 开发起来确实要简单许多，spring boot 包含了 spring mvc ;内置tomcat ;启动只需要主方法即可

1.使用idea新建一个spring boot项目

　　file----new 一个project 选择 Spring Initializr 然后next

到这里一个基本的springboot项目已经可以了

接下来我们新建4个包； controller ,dao , entity, service

基本目录建好以后，开始配置 application.properties 视图解析路径以及数据库配置

#前端视图展示采用jsp
spring.mvc.view.prefix=/jsp/
spring.mvc.view.suffix=.jsp


#数据库配置

spring.datasource.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&characterSetResults=utf8 
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
mybatis.mapper-locations=classpath:mapper/*.xml

视图和数据库配置好以后，接下来编写mapper文件和sql语句

我们在源文件下添加mapper文件夹

再编写我们用于测试的mapper也就是mybatis写sql语句的；就取名叫UserMapper.xml吧

<?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.example.demo.dao.UserDao">  //这里是接口的路径
    <select id="getList" resultType="com.example.demo.entity.User">
        select id,name,password from  tb_user
    </select>
</mapper>

xml写好以后，我们开始写dao层接口和返回的entity类

public class User {


    private  String  id;
    private String name;
    private  String  password;

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getPassword() {
        return password;
    }

接口

public interface UserDao {
    List<User> getList();

}

service

@Service
public class UserService {

    @Autowired
    private UserDao userdao;

    public List<User> getList(){
        return userdao.getList();
    }
}

最后编写我们的访问层

@Controller
public class UserController {
    @Autowired
    private UserService userService;

    @RequestMapping("/test")
    @ResponseBody
    public List<User> test01(){
        System.out.println(123);
        return userService.getList();
    }

    @RequestMapping("/test2")
    public String test02(){
        System.out.println(1234);
        return "index";
    }

}

到这一步不访问页面的配置基本完成了，现在回来看项目启动类；和java目录同级

@SpringBootApplication
@MapperScan("com.example.demo.dao")//扫描接口
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

这个时候已经可以正常启动项目了。直接运行此main方法；

添加页面和js案例

首页页面时默认放在webapp文件下的，我们先建一个webapp文件夹

在webapp文件下建jsp和static两个文件，一个用于放置页面，一个用于放置js

jsp页面

<head>


</head>
<body>

123456

<script type="text/javascript" src="../static/My.js"></script>
<script type="text/javascript">
    alert(test());
</script>

</body>

js文件

function test() {
    return 1;
}

到这里案例已经完成啦；访问第一个返回json格式的数据。访问第二个返回页面。并且引用了js文件

　　最下面是pom.xml

<?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>2.0.3.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-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- tomcat 的支持.-->

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-tomcat</artifactId>

            <scope>provided</scope>

        </dependency>

        <dependency>

            <groupId>org.apache.tomcat.embed</groupId>

            <artifactId>tomcat-embed-jasper</artifactId>

            <scope>provided</scope>

        </dependency>

        <!-- MySql驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.21</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.9</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>




</project>

如果案例写出来有问题。启动不了。或者访问404；请先修改文件目录和此案例一样，然后再自己理解和修改

最后给出整个项目的的结构图