springboot第三天

程序员文章站 2024-03-23 23:15:58

...

springboot第三天

SpringBoot Web开发

创建应用，选择启动器
https://docs.spring.io/spring-boot/docs/2.2.6.RELEASE/reference/html/using-spring-boot.html#using-boot-starter

xxxAUtoConfiguration：向容器中自动配置组件

xxxxProperties：自动配置类，装配配置文件中自定义的一些内容。

要解决的问题：

导入静态资源
首页
jsp，模板引擎Thymeleaf
装配扩展SpringMVC
增删改查
拦截器
国际化

静态资源导入

public void addResourceHandlers(ResourceHandlerRegistry registry) {
    if (!this.resourceProperties.isAddMappings()) {
        logger.debug("Default resource handling disabled");
    } else {
        Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
        CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
        if (!registry.hasMappingForPattern("/webjars/**")) {
            this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
        }

        String staticPathPattern = this.mvcProperties.getStaticPathPattern();
        if (!registry.hasMappingForPattern(staticPathPattern)) {
            this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(WebMvcAutoConfiguration.getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
        }

    }
}

webjars：在项目中引入的静态资源，自动去/META-INF/resources/webjars/下找

[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-jxtp8KZ8-1588345120201)(F:\spring boot\Snipaste_2020-04-27_21-44-19.png)]

https://www.webjars.org/

该网站下可以以jar包引入前端资源，在该网站下载的资源都符合以上方式。

springboot静态资源存放位置可以是如下四个位置，匹配/**的访问请求会默认到这四个文件夹下去寻找资源

“classpath:/META-INF/resources/”, 这个就是在引入的jar包中去找资源

“classpath:/resources/”, 优先级最高

“classpath:/static/”, 优先级其次默认值

"classpath:/public/"优先级最低

 CLASSPATH_RESOURCE_LOCATIONS = new String[]{"classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/"};

设置主页面

@Bean
public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext, FormattingConversionService mvcConversionService, ResourceUrlProvider mvcResourceUrlProvider) {
    WelcomePageHandlerMapping welcomePageHandlerMapping = new WelcomePageHandlerMapping(new TemplateAvailabilityProviders(applicationContext), applicationContext, this.getWelcomePage(), this.mvcProperties.getStaticPathPattern());
    welcomePageHandlerMapping.setInterceptors(this.getInterceptors(mvcConversionService, mvcResourceUrlProvider));
    return welcomePageHandlerMapping;
}

private Optional<Resource> getWelcomePage() {
    String[] locations = WebMvcAutoConfiguration.getResourceLocations(this.resourceProperties.getStaticLocations());
    return Arrays.stream(locations).map(this::getIndexHtml).filter(this::isReadable).findFirst();
}

private Resource getIndexHtml(String location) {
    return this.resourceLoader.getResource(location + "index.html");
}

写一个为index的页面放在静态资源存放位置中，会自动给跳转到该界面

设置页面图标

@Configuration
@ConditionalOnProperty(
    value = {"spring.mvc.favicon.enabled"},
    matchIfMissing = true
)
public static class FaviconConfiguration implements ResourceLoaderAware {
    private final ResourceProperties resourceProperties;
    private ResourceLoader resourceLoader;

    public FaviconConfiguration(ResourceProperties resourceProperties) {
        this.resourceProperties = resourceProperties;
    }

    public void setResourceLoader(ResourceLoader resourceLoader) {
        this.resourceLoader = resourceLoader;
    }

    @Bean
    public SimpleUrlHandlerMapping faviconHandlerMapping() {
        SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
        mapping.setOrder(-2147483647);
        mapping.setUrlMap(Collections.singletonMap("**/favicon.ico", this.faviconRequestHandler()));
        return mapping;
    }

第一步关闭默认图标

在配置文件中设置

sring.mvc.favicon.enabled=false

第二步

把名为favicon的图片放入静态资源夹

[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-iOnU7QA7-1588345120205)(Snipaste_2020-04-30_16-07-27.png)]

模板引擎

[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-4uEKKGo9-1588345120209)(Snipaste_2020-04-30_16-11-50.png)]

只要需要使用thymeleaf，只需要导入依赖就可以，把heml页面放在templates之中

引入Thymeleaf我们都是基于3.x开发的

<dependency>
   <groupId>org.thymeleaf</groupId>
   <artifactId>thymeleaf-spring5</artifactId>
</dependency>
<dependency>
   <groupId>org.thymeleaf.extras</groupId>
   <artifactId>thymeleaf-extras-java8time</artifactId>
</dependency>

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

替换warjars

使用方法

导入命名空间

<html lang="en" xmlns:th="http://www.thymeleaf.org">

1）、th:text；改变当前元素里面的文本内容；

th:utext:改变当前元素里面的文本内容，不转义

th:each :遍历集合中的每个元素

<h1 th:each="user:${users}" th:text="${user}"></h1>

th：任意html属性；来替换原生属性的值

2）、表达式？t

Simple expressions:（表达式语法）
Variable Expressions: ${…}：获取变量值；OGNL；
1）、获取对象的属性、调用方法
2）、使用内置的基本对象：
#ctx : the context object.
#vars: the context variables.
#locale : the context locale.
#request : (only in Web Contexts) the HttpServletRequest object.
#response : (only in Web Contexts) the HttpServletResponse object.
#session : (only in Web Contexts) the HttpSession object.
#servletContext : (only in Web Contexts) the ServletContext object.

            ${session.foo}
        3）、内置的一些工具对象：

#execInfo : information about the template being processed.
#messages : methods for obtaining externalized messages inside variables expressions, in the same way as they would be obtained using #{…} syntax.
#uris : methods for escaping parts of URLs/URIs
#conversions : methods for executing the configured conversion service (if any).
#dates : methods for java.util.Date objects: formatting, component extraction, etc.
#calendars : analogous to #dates , but for java.util.Calendar objects.
#numbers : methods for formatting numeric objects.
#strings : methods for String objects: contains, startsWith, prepending/appending, etc.
#objects : methods for objects in general.
#bools : methods for boolean evaluation.
#arrays : methods for arrays.
#lists : methods for lists.
#sets : methods for sets.
#maps : methods for maps.
#aggregates : methods for creating aggregates on arrays or collections.
#ids : methods for dealing with id attributes that might be repeated (for example, as a result of an iteration).

Selection Variable Expressions: *{...}：选择表达式：和${}在功能上是一样；
	补充：配合 th:object="${session.user}：

Name: Sebastian.

Surname: Pepper.

Nationality: Saturn.

Message Expressions: #{...}：获取国际化内容
Link URL Expressions: @{...}：定义URL；
		@{/order/process(execId=${execId},execType='FAST')}
Fragment Expressions: ~{...}：片段引用表达式
		<div th:insert="~{commons :: main}">...</div>

Literals（字面量）
Text literals: ‘one text’ , ‘Another one!’ ,…
Number literals: 0 , 34 , 3.0 , 12.3 ,…
Boolean literals: true , false
Null literal: null
Literal tokens: one , sometext , main ,…
Text operations:（文本操作）
String concatenation: +
Literal substitutions: |The name is ${name}|
Arithmetic operations:（数学运算）
Binary operators: + , - , * , / , %)
Minus sign (unary operator): -
Boolean operations:（布尔运算）
Binary operators: and , or
Boolean negation (unary operator): ! , not
Comparisons and equality:（比较运算）
Comparators: > , < , >= , <= ( gt , lt , ge , le )
Equality operators: == , != ( eq , ne )
Conditional operators:条件运算（三元运算符）
If-then: (if) ? (then)
If-then-else: (if) ? (then) : (else)
Default: (value) ?: (defaultvalue)
Special tokens:
No-Operation: _

[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-qM5bCxrc-1588345120214)(Snipaste_2020-04-30_20-53-30.png)]

扩展装配SPringMVC

扩展只需要定义一个类，一u定要有注释@Config

ration,不能有@EnableWebMvc（这个注解就是导入一个类DelegatingWebMvcConfiguration）并且该类必须是一个WebMvcConfigurer,会自动把该类注入到容器中，该类会放在config包下

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import java.util.Locale;
@Configuration
public class MyConfig implements WebMvcConfigurer {

    @Bean
    public ViewResolver  myViewResolver(){
        return new MyViewResolver();
    }
    public static class MyViewResolver implements ViewResolver{

        @Override
        public View resolveViewName(String s, Locale locale) throws Exception {
            return null;
        }
    }
}

所有自动配置原理都是一样的，首先看看有没有用户配置的，没有就用自动配置的，如果有些组件可以存在多个，就会把用户配置的和自己自动配置的结合起来

添加一个视图控制器

public class MyConfig implements WebMvcConfigurer {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/b").setViewName("test");
    }
}

springboot中，有大量的xxxConfigurer帮助我们进行扩展配置，只要看见了，就需要注意扩展了什么功能。

实例

引入依赖lombok

<dependency>
   <groupId>org.projectlombok</groupId>
   <artifactId>lombok</artifactId>
</dependency>

实体类

@Data
@NoArgsConstructor
public class Employee {
    private Integer id;
    private String lastName;
    private String email;
    private Integer gender;
    private Department department;
    private Date birth;

    public Employee(Integer id, String lastName,String email,Integer gender, Department department) {
        this.id = id;
        this.lastName = lastName;
        this.email = email;
        this.gender = gender;
        this.department = department;
        this.birth = new Date();
    }

}

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Department {
    private Integer id;
    private String departmentName;
}

Dao层

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
@Repository
public class EmployeeDao {
    private static Map<Integer,Employee> employees= null;
    @Autowired
    private static DepartmentDao departmentDao;
    static{
        employees=new HashMap<Integer,Employee>();
        employees.put(1002,new Employee(1002,"AA","sadas.com",0,new Department(101,"教育部")));
        employees.put(1001,new Employee(1001,"AS","ASDASD.com",1,new Department(101,"教育部")));
        employees.put(1003,new Employee(1003,"AB","sadas.com",0,new Department(101,"教育部")));
    }
    private Integer initId=1006;
    public void addEmpolyee(Employee employee){
        if(employee.getId()==null){
            employee.setId(initId++);
        }
        employee.setDepartment(departmentDao.getDepartmentById(employee.getId()));
        employees.put(employee.getId(),employee);

    }
    public Collection<Employee> fingAll(){
        return employees.values();
    }
    public Employee getEmployeeById(Integer id){
        return employees.get(id);
    }
    public void deleteEmployee(Integer id){
        employees.remove(id);
    }
}

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
@Repository
public class DepartmentDao {
    private static Map<Integer,Department> departments= null;
    static{
        departments=new HashMap<Integer, Department>() ;
        departments.put(101,new Department(101,"教育部"));
        departments.put(102,new Department(102,"学生部"));
        departments.put(103,new Department(103,"运输部"));
        departments.put(104,new Department(104,"总理部"));
        departments.put(105,new Department(105,"医学部"));
    }
    public Collection<Department> getDepartment(){
        return departments.values();
    }
    public Department getDepartmentById(Integer id){
        return departments.get(id);
    }
}

配置首页所有静态资源都需要使用thymeleaf接管。

页面国际化

国际化的自动配置类： MessageSourceAutoConfiguration

在资源目录下建立一个文件夹名称是i18n

建立properties文件，名称格式为：名称+国家名字缩写+语言缩写

用下划线相连，idea会自动创建一个文件Resource Bundle ‘名称’

[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-umzXeDar-1588345120217)(Snipaste_2020-05-01_20-48-25.png)]

[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-nwgX8EKZ-1588345120220)(Snipaste_2020-05-01_20-48-57.png)]

[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-TzQ14cbt-1588345120221)(Snipaste_2020-05-01_20-50-20.png)]

在主配置文件中警醒如下设置：

spring.messages.basename=i18n.login

i18n.login是国际化配置文件所在地

在前端页面中使用#{…}来进行国际化

自定义LocaleResolver

public class MyLocalReserver implements LocaleResolver {
    /**
     * 解析请求
     * @param httpServletRequest
     * @return
     */
    @Override
    public Locale resolveLocale(HttpServletRequest httpServletRequest) {
        String language=httpServletRequest.getParameter("l");
        Locale locale=Locale.getDefault();
        //如果请求链接携带了国际化参数
        if(StringUtils.isEmpty(language)){
            String[] split=language.split("_");
            locale=new Locale(split[0],split[1]);
        }
        return locale;
    }

    @Override
    public void setLocale(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Locale locale) {

    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class MyConfig implements WebMvcConfigurer {


    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index.html");
        registry.addViewController("/index").setViewName("index.html");
    }
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocalReserver();
        }
}
port org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class MyConfig implements WebMvcConfigurer {


    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index.html");
        registry.addViewController("/index").setViewName("index.html");
    }
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocalReserver();
        }
}

springboot第三天

springboot第三天

SpringBoot Web开发

模板引擎

添加一个视图控制器

实例

引入依赖lombok

实体类

Dao层

页面国际化

SpringBoot第三天 - Lombok

springboot第三天

springboot 使用session实现一个简单的部门管理系统

SpringMVC接受参数 SpringBoot接收参数 Controller接收参数

SpringBoot2 Controller接收参数的方式

SpringBoot 系列教程(九十三)：Spring Boot整合Activiti6.0工作流

vue+Springboot 前后端数据交互(1)

快速学习-springBoot入门

SpringBoot快速入门

SpringBoot简介及入门