SpringBoot的配置详解

SpringBoot是基于约定的，所以很多配置都有默认值，但如果想使用自己的配置替换默认配置的话，就可以使用application.properties或者application.yml（application.yaml）进行配置。 SpringBoot默认会从Resources目录下加载application.properties或application.yml（application.yaml）文件

一、application.yml

YML文件格式是YAML (YAML Aint Markup Language)编写的文件格式，YAML是一种直观的能够被电脑识别的的数 据数据序列化格式，并且容易被人类阅读，容易和脚本语言交互的，可以被支持YAML库的不同的编程语言程序导 入，比如： C/C++, Ruby, Python, Java, Perl, C#, PHP等。YML文件是以数据为核心的，比传统的xml方式更加简洁。 YML文件的扩展名可以使用.yml或者.yaml

1.配置普通数据

语法： key: value

name: tracy

注意：value之前有一个空格

2.配置对象数据

语法：

key:
   key1: value1
   key2: value2

或者： key: {key1: value1,key2: value2}

示例：

#对象数据
user:
    name: tracy
    age: 25
    address: shenzhen

#行内
user: {name: tracy,age: 25,address: shenzhen}

3.配置Map数据（与对象数据配置相同）

key:
   key1: value1
   key2: value2

#Map(与对象配置相同)
userMap:
   name: hcx
   age: 24

4.配置集合数据

语法：

key:
  - value1
  - value2
或者：
key: [value1,value2]

示例：

#配置普通字符串集合
city:
  - beijing
  - shanghai
  - guangzhou
  - shenzhen

city: [beijing,shanghai,guangzhou,shenzhen]

#配置对象集合
student:
  - name: tracy
    age: 25
    address: shenzhen
  - name: hcx
    age: 24
    address: gaungzhou

student: [{name: tracy,age: 25,address: shenzhen},{name: hcx,age: 24,address: gaungzhou}]

二、 配置文件与配置类的属性映射方式

1.使用@Value注解映射

@Value注解将配置文件中的值映射到一个Spring管理的Bean的字段上

package com.hcx.springbootdemo.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * Created by hongcaixia on 2020/2/10.
 */
@Controller
public class ConfigController {

    @Value("${name}")
    private String name;

    @Value("${user.address}")
    private String address;

    @RequestMapping("/config")
    @ResponseBody
    public String config(){
        System.out.println(name);
        return "hello,"+name+","+address;
    }
}

2.使用@ConfigurationProperties注解映射

通过注解@ConfigurationProperties(prefix="配置文件中的key的前缀")可以将配置文件中的配置自动与实体进行映射

添加执行器依赖：（配置了可以在写配置文件时有提示）

<!--@ConfigurationProperties执行器-->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-configuration-processor</artifactId>
	<optional>true</optional>
</dependency>

package com.hcx.springbootdemo.controller;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * Created by hongcaixia on 2020/2/10.
 */
@Controller
@ConfigurationProperties(prefix = "worker")//自动从配置文件中找出worker开头的
public class ConfigController {

    private String name;
    private String address;
    private String age;

    @RequestMapping("/config")
    @ResponseBody
    public String config(){
        System.out.println(name);
        return name+age+address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }
}

注意：使用@ConfigurationProperties方式可以进行配置文件与实体字段的自动映射，字段必须提供set方法才可以，而使用@Value注解修饰的字段不需要提供set方法

demo：

JdbcProperties:

package com.hcx.config;

import org.springframework.boot.context.properties.ConfigurationProperties;

/**
 * Created by hongcaixia on 2020/2/11.
 */
@ConfigurationProperties(prefix = "jdbc")
public class JdbcProperties {

    private String driverClassName;
    private String url;
    private String username;
    private String password;

    public String getDriverClassName() {
        return driverClassName;
    }

    public void setDriverClassName(String driverClassName) {
        this.driverClassName = driverClassName;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    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;
    }
}

方式一：通过注入：

package com.hcx.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;


/**
 * Created by hongcaixia on 2020/2/10.
 */
@EnableConfigurationProperties(JdbcProperties.class)
public class JdbcConfiguration {

    //通过注入的方式
    @Autowired
    private JdbcProperties jdbcProperties;

    @Bean //把方法的返回值注入到spring容器
    public DataSource dataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.jdbcProperties.getDriverClassName());
        dataSource.setUrl(this.jdbcProperties.getUrl());
        dataSource.setUsername(this.jdbcProperties.getUsername());
        dataSource.setPassword(this.jdbcProperties.getPassword());
        return dataSource;
    }
}

方式二：通过方法形参：

package com.hcx.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;


/**
 * Created by hongcaixia on 2020/2/10.
 */
@EnableConfigurationProperties(JdbcProperties.class)
public class JdbcConfiguration {

    /**
     * 通过方法形参传递
     * @param jdbcProperties 形参
     * @return
     */
    @Bean //把方法的返回值注入到spring容器
    public DataSource dataSource(JdbcProperties jdbcProperties){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(jdbcProperties.getDriverClassName());
        dataSource.setUrl(jdbcProperties.getUrl());
        dataSource.setUsername(jdbcProperties.getUsername());
        dataSource.setPassword(jdbcProperties.getPassword());
        return dataSource;
    }


}

方式三：把注解@ConfigurationProperties作用于方法上

package com.hcx.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;


/**
 * Created by hongcaixia on 2020/2/10.
 */
@EnableConfigurationProperties(JdbcProperties.class)
public class JdbcConfiguration {

    @Bean //把方法的返回值注入到spring容器
    @ConfigurationProperties(prefix = "jdbc")
    public DataSource dataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        return dataSource;
    }
    
}

三、静态资源文件位置

访问路径：ip地址:端口号/项目根路径/静态资源文件名

四、拦截器

1.自定义拦截器：实现HandlerInterceptor接口

MyInterceptor：

package com.hcx.interceptor;

import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

/**
 * 定义拦截器
 * Created by hongcaixia on 2020/2/11.
 */
@Component
public class MyInterceptor implements HandlerInterceptor{

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("前置方法执行了");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
        System.out.println("后置方法执行了");
    }
}

2.配置拦截器，自定义一个Java配置类（@Configuration），实现WebMvcConfigurer接口。

WebMvcConfiguration:

package com.hcx.config;

import com.hcx.interceptor.MyInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * 配置拦截器
 * Created by hongcaixia on 2020/2/11.
 */
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer{

    @Autowired
    private MyInterceptor myInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor).addPathPatterns("/**");
    }
}