IDEA 创建 SpringBoot 时遇到的一些问题

我就是我 2022-05-25 03:51 298阅读 0赞

### 创建一个SpringBoot项目 ###

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![这里写图片描述][70 1]

![这里写图片描述][70 2]

### Pom.xml 配置 ###

<?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.siwei</groupId>
        <artifactId>girl</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>girl</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/> 
        </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>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-configuration-processor</artifactId>
                <optional>true</optional>
            </dependency>
    
            
            
                
                
            
    
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>
    
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
    
    
    
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    
    </project>

### 配置yml文件实现多环境 ###

![这里写图片描述][70 3]

1 `application.yml`

spring:
      profiles:
        active: dev
    
    
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/testdb
        username: root
        password:
      jpa:
        hibernate:
          ddl-auto: update
        show-sql: false

2 `application-dev.yml`

server:
      port: 8082
    
    
    test:
      name: C
      age: 20
      content: "age: ${test.name},age: ${test.age}"

3 `application-prod.yml`

server:
      port: 8081
      servlet:
        context-path: /girl
    
    
    test:
      name: F
      age: 18
      content: "age: ${test.name},age: ${test.age}"

### 使用 SpringBootApplication 报错 ###

当你使用 `@SpringBootApplication` 可能会提示  
`Generating Your Own Metadata by Using the Annotation Processor`.

解决办法：  
按照文档，在 `pom.xml` 中添加 `dependency`。  
![这里写图片描述][70 4]

### 常见的restful注解 ###

rest = controller + responseJson  
       requestMapping {‘A’,’B’}
    
    5 @PathVariable          获取Url中的数据
    @RequestMapping(value = {
       "/hi/{id}"},method = RequestMethod.GET)
    public String say(@PathVariable("id") Integer id ){
    
       @RequestParam      获取请求参数的值
    @RequestMapping(value = {
       "/say"},method = RequestMethod.GET)
    public String say(@RequestParam(value = "id", required = false, defaultValue = "0") Integer myID ){
    
       @GetMapping          组合注解
    @RequestMapping(value = {
       "/say"},method = RequestMethod.GET)
    等同于
    @GetMapping(value = {
       "/say"})

### `findOne` 在 `SpringBoot2`以后的错误 ###

使用 findOne 获取具体id 的数据，报错：spring boot 2.0 findOne Type S  
![这里写图片描述][70 5]

两种解决办法：  
1 把 SB 版本从2.1 -> 到 1.5.10  
2 `return girlRepository.findById(id).get();`

*  `PUT` 方式使用 `x-www-form-urlencoded`
 *  `MyIsAM` 不支持事物

[70]: /images/20220525/6db6b6d06a704806890d48fae24c8b3f.png
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