SpringBoot基础第二天

SpringBoot对静态资源的映射:

(1) 要在src/main/resources文件夹下创建static和templates两个文件夹staitc存储静态资源,templates存储模板引擎

(2)要在pom.xml依赖下导入依赖

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

如果导入依赖失败的话可以尝试添加版本号

示例:创建名为success的页面并可以访问

首先在templates文件夹下创建网页

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Title</title>
</head>
<body>
<div  th:text="${hello}"> </div>
</body>
</html>

这里的${hello}可以联想成Vue中的{{}}表达式，这里调用了控制器中的方法

然后在控制器写方法

@RequestMapping("/success")
public String hello(Model model){
    model.addAttribute("hello","<h1>zhangsan</h1>");
    return "success";
}

启动服务器就可以通过端口号进行访问

Thymeleaf语法

(1)变量表达式:

变量表达式即OGNL表达式或Spring EL表达式(在Spring术语中也叫model attributes)。如下所示： ${session.user.name}
它们将以HTML标签的一个属性来表示：
<span th:text="${book.author.name}">

(2)选择表达式

选择表达式很像变量表达式，不过它们用一个预先选择的对象来代替上下文变量容器(map)来执行，如下： *{customer.name}
被指定的object由th:object属性定义：
<div th:object="${book}"> 
 ... 
 <span th:text="*{title}">...</span> 
 ... 
</div>

(3) URL表达式

URL表达式指的是把一个有用的上下文或回话信息添加到URL，这个过程经常被叫做URL重写。不需要指定项目名字
@{/order/list} 
URL还可以设置参数： 
@{/order/details(id=${orderId})} 
让我们看这些表达式：

<form th:action="@{/createOrder}"> 
<a href="main.html" rel="external nofollow" th:href="@{/main}" rel="external n

表达式支持的语法

字面（Literals）
•	文本文字（Text literals）: 'one text', 'Another one!',…
•	数字文本（Number literals）: 0, 34, 3.0, 12.3,…
•	布尔文本（Boolean literals）: true, false
•	空（Null literal）: null
•	文字标记（Literal tokens）: one, sometext, main,…
文本操作（Text operations）
•	字符串连接(String concatenation): +
•	文本替换（Literal substitutions）: |The name is ${name}|
算术运算（Arithmetic operations）
•	二元运算符（Binary operators）: +, -, *, /, %
•	减号（单目运算符）Minus sign (unary operator): -
布尔操作（Boolean operations）
•	二元运算符（Binary operators）:and, or
•	布尔否定（一元运算符）Boolean negation (unary operator):!, not
比较和等价(Comparisons and equality)
•	比较（Comparators）: >, <, >=, <= (gt, lt, ge, le)
•	等值运算符（Equality operators）:==, != (eq, ne)
条件运算符（Conditional operators）
If-then: (if) ? (then)
If-then-else: (if) ? (then) : (else)
Default: (value) ?: (defaultvalue)

常用的thymeleaf标签

视图控制器:

   @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/login").setViewName("login");
        registry.addViewController("/header").setViewName("header");
        registry.addViewController("/index").setViewName("index");
        registry.addViewController("/menu").setViewName("menu");
        registry.addViewController("/add").setViewName("add");
        registry.addViewController("/update").setViewName("update");
        registry.addViewController("/test").setViewName("test");

    }

拦截器

方法

package com.qcby.DruidConfig;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("前置拦截");
        return true;
    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("后置拦截");
    }
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("最终拦截");
    }
}

@Override
public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(new MyInterceptor())
            .addPathPatterns("/**")
            .excludePathPatterns("/hello2");
}

编写Servlet类:

@Bean
public ServletRegistrationBean myServlet(){
    ServletRegistrationBean registrationBean = new ServletRegistrationBean(new
            MyServlet(),"/myServlet");
    return registrationBean;
}

编写测试类

package com.qcby.Controller;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class MyServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException {
        super.doGet(httpServletRequest,httpServletResponse);
        System.out.println("get方法执行了");
    }

    @Override
    protected void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException {
        super.doPost(httpServletRequest,httpServletResponse);
        System.out.println("Post方法执行了");
    }
}

网页编写

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="/myServlet" method="post">
    <input type="text"></br>
    <input type="submit" value="提交">
</form>
</body>
</html>

输出结果

说明配置Servlet方法调用成功

编写Filter

 @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new MyFilter());
        registrationBean.setUrlPatterns(Arrays.asList("/hello","/test"));
        return registrationBean;
    }

@Bean中要求对/hello /test路径的进行过滤

package com.qcby.Controller;

import javax.servlet.*;
import java.io.IOException;

public class MyFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("过滤器初始化");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("处理中");
    }

    @Override
    public void destroy() {
        System.out.println("过滤器结束了");
    }
}

监听器

 @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean<MyListener> registrationBean = new
                ServletListenerRegistrationBean<>(new MyListener());
        return registrationBean;
    }

package com.qcby.Controller;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class MyListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        System.out.println("监听器初始化成功");
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {
        System.out.println("监听器摧毁");
    }
}

SpringBoot数据层开发

需要导入的依赖

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
   <groupId>org.apache.commons</groupId>
   <artifactId>commons-dbcp2</artifactId>
</dependency>

<dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <scope>runtime</scope>
</dependency>

在application.yaml中配置数据库的驱动用户名密码

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/boot_demo
    driver-class-name: com.mysql.jdbc.Driver
    type: com.zaxxer.hikari.HikariDataSource

配置druid数据库的话

导入依赖

<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>druid</artifactId>
   <version>1.0.9</version>
</dependency>
<dependency>
   <groupId>log4j</groupId>
   <artifactId>log4j</artifactId>
   <version>1.2.15</version>
</dependency>

同上在yaml中配置数据库的基本信息

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/boot_demo
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

创建数据源注册类(可以写在启动类上不要放在MvcConfig类中,也可以单独写一个配置类)

@Configuration
public class DruidConfig {

    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource dataSource(){
        return new DruidDataSource();
    }
}