springBoot整合mybatis、jsp 或 HTML

springBoot整合mybatis、jsp

Spring Boot的主要优点：

1：  为所有Spring开发者更快的入门；

2：  开箱即用，提供各种默认配置来简化项目配置；

3：  内嵌式容器简化Web项目；

4：  没有冗余代码生成和XML配置的要求

本项目使用到的工具：

• 开发工具：Intellij IDEA 2018.1.4
• springboot:2.0.1.RELEASE
• jdk：1.8.0_40
• maven:3.3.9

开始搭建：

项目创建

finish即可。

建好后的 项目结构：

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.dengwei</groupId>
     <artifactId>springdemo</artifactId>
     <version>0.0.1-SNAPSHOT</version>
     <packaging>jar</packaging>

     <name>springdemo</name>
     <description>Demo project for Spring Boot</description>

     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
         <version>2.0.1.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-jdbc</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
         <dependency>
             <groupId>org.mybatis.spring.boot</groupId>
             <artifactId>mybatis-spring-boot-starter</artifactId>
             <version>1.3.2</version>
         </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>

         <!--springBoot整合jsp-->
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-tomcat</artifactId>
         </dependency>
         <dependency>
             <groupId>org.apache.tomcat.embed</groupId>
             <artifactId>tomcat-embed-jasper</artifactId>
         </dependency>
     </dependencies>

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

 </project>

我们先建一个controller层，写一个简单的类访问一下：

HelloSpringBootController:

 package com.dengwei.springdemo.controller;

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

 import java.util.HashMap;
 import java.util.Map;

 @RestController
 public class HelloSpringBootController {
     @RequestMapping("/index")
     public String hello(){
         return "hello springBoot";
     }

     @RequestMapping("/hello")
     public Map<String,String> getMap(){
         HashMap<String, String> map = new HashMap<String,String>();
         map.put("key1","姓名");
         map.put("key2","年龄");
         map.put("key3","性别");
         return map;
     }

 }

下面我们启动一下：

每一个springBoot项目中都有一个XXXAplication类，这个类就是springBoot的启动类。

注意：因为我们前面添加了数据库相关的依赖，但是我们还没有具体配置，如果直接运行的话会报错：

***************************
APPLICATION FAILED TO START
***************************
Description:
Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified and no embedded datasource could be auto-configured.
Reason: Failed to determine a suitable driver class
Action:
Consider the following:
If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.

If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

解决：

在@EnableAutoConfiguretion中添加   exclude= {DataSourceAutoConfiguration.class}，排除此类的autoconfig。启动以后就可以正常运行。

好的，启动没问题，我们下面正式进入mybatis与jsp的整合：

建model层：

 package com.dengwei.springdemo.model;

 public class User {
     private Integer id;
     private String userName;
     private String password;

     public Integer getId() {
         return id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     public String getUserName() {
         return userName;
     }

     public void setUserName(String userName) {
         this.userName = userName;
     }

     public String getPassword() {
         return password;
     }

     public void setPassword(String password) {
         this.password = password;
     }

     @Override
     public String toString() {
         return "User{" +
                 "id=" + id +
                 ", userName='" + userName + '\'' +
                 ", password='" + password + '\'' +
                 '}';
     }
 }

2：建mapper层：

注意：我们这里的sql语句是通过注解的形式和接口写在一起的，也可以通过xml的形式配置，可以见另外一篇博客：

 package com.dengwei.springdemo.mapper;

 import com.dengwei.springdemo.model.User;
 import org.apache.ibatis.annotations.Param;
 import org.apache.ibatis.annotations.Select;

 public interface IUserMapper {

     @Select("SELECT id,user_name userName, pass_word password FROM user WHERE id = #{id}")
     User queryById(@Param("id") Integer id);
 }

3：建Service层：

 package com.dengwei.springdemo.Service;

 import com.dengwei.springdemo.mapper.IUserMapper;
 import com.dengwei.springdemo.model.User;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;

 @Service
 public class UserService {
     @Autowired
     private IUserMapper userMapper;
     public User queryUser(Integer id){
         return  userMapper.queryById(id);
     }
 }

4：控制层访问：

 package com.dengwei.springdemo.controller;

 import com.dengwei.springdemo.Service.UserService;
 import com.dengwei.springdemo.model.User;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;

 @Controller
 @RequestMapping("/controller")
 public class UserController {
     @Autowired
     private UserService userService;

     @RequestMapping("/user")
     @ResponseBody
     public User getUser(Integer id){
         User user = userService.queryUser(id);
         return user;
     }

 }

数据库连接配置文件：

 spring.mvc.view.prefix=/WEB-INF/jsp/
 spring.mvc.view.suffix=.jsp
 #jdbc相关
 spring.datasource.url=jdbc:mysql://localhost:3306/floor_shop
 spring.datasource.username=root
 spring.datasource.password=admin
 spring.datasource.driver-class-name=com.mysql.jdbc.Driver

启动springBoot:

注意：前面我们排除了对数据库相关的自动配置，现在我们配置了数据库实体配置，所以把之前的排除要删掉，并且多添加@MapperScan("mapper映射文件的地址")

 package com.dengwei.springdemo;

 import org.mybatis.spring.annotation.MapperScan;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;

 @SpringBootApplication
 @EnableAutoConfiguration
 @MapperScan("com.dengwei.springdemo.mapper")
 public class SpringdemoApplication {

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

好的直接启动即可。上面我们简单实现了数据库的查询，增删改就自己取写一写吧。

下面我们看看springBoot整合jsp:

1、在原来的依赖中添加依赖：

 <!--对jsp访问的支持-->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
        </dependency>

2、跳转页面：

 springBoot整合thymeleaf：

 <!--模板引擎thmeleaf对HTML的支持-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

跳转页面：

不用加前后缀，可以直接跳转页面：

关于thymeleaf的基础使用参考：

https://www.jianshu.com/p/6953671d4645

在我们第一次新建的HelloSpringBootController中 新建一个helloJsp()方法，注意：我们之前用的注解是@RestController ,这个注解相当于@Controller  +  @ResponseBody

表示标注的类或则方法返回的都是json格式的，而我们这次需要访问jsp页面所以需要换成@Controller注解。在需要的返回json格式的方法上添加@ResponseBody，而不是整个类的所有方法都返回json格式。

下面我们看一下springBoot中的全局异常捕获：

异常捕获的核心标签：@ControllerAdvice   +   @ExceptionHandler(RuntimeException.class)

 package com.dengwei.springdemo.controller;

 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RequestMapping;

 @ControllerAdvice
 public class GlobalExceptionHandler {
     @ExceptionHandler(RuntimeException.class)
     @RequestMapping
     public String errorPage(){
         return "index";
     }
 }

好了，就先到这儿吧！