SpringBoot获取配置文件信息

落日映苍穹つ 2022-05-22 10:38 363阅读 0赞

默认application.properties中的信息：

local.ip=192.168.238.133
    local.port=8080

# 一、Environment（一） #

直接在SpringBoot启动类main方法中：

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    @SpringBootApplication
    public class App {
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
            String port = context.getEnvironment().getProperty("local.port");
            System.out.println(port);
        }
    
    }

# 二、Environment（二） #

在SpringBoot启动类App，下级新建ConfigurationFile：

import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.core.env.Environment;
    import org.springframework.stereotype.Component;
    
    @Component
    public class ConfigurationFile { 
    
        @Autowired
        private Environment environment;
    
        public void getConfigInfo (){
            String ip = environment.getProperty("local.ip");
            System.out.println("ip = " + ip);
        }
    
    }

App.java

import com.xh.config.ConfigurationFile;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    @SpringBootApplication
    public class App {
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
            ConfigurationFile configurationFile = context.getBean(ConfigurationFile.class);
            configurationFile.getConfigInfo();
        }
    
    }

# 三、使用@value注解 #

在SpringBoot扫描包下新建ServerInfo.java：

import org.springframework.beans.factory.annotation.Value;
    import org.springframework.stereotype.Component;
    
    @Component
    public class ServerInfo { 
    
        @Value("${local.ip}")
        private String ip;
    
        @Value("${local.port}")
        private Integer port;
    
        public String getIp() {
            return ip;
        }
    
        public void setIp(String ip) {
            this.ip = ip;
        }
    
        public Integer getPort() {
            return port;
        }
    
        public void setPort(Integer port) {
            this.port = port;
        }
    
        @Override
        public String toString() {
            return "ServerInfo{" +
                    "ip='" + ip + '\'' +
                    ", port=" + port +
                    '}';
        }
    }

App.java

import com.xh.config.ServerInfo;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    @SpringBootApplication
    public class App {
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
            ServerInfo serverInfo = context.getBean(ServerInfo.class);
            System.out.println(serverInfo);
        }
    
    }

注意： @Value(“$\{local.port\}”)中，local.port必须在加载的配置文件中，可以为空，不然会出现类似于`Could not resolve placeholder 'local.ipq' in value "${local.ipq}"` 的错误。

如果没有配置项，可以给默认值，例：`@Value("${local.ipq:192.168.238.145}")` ， 而我的配置文件中没有local.ipq项也不会报错。

# 四、变量的引用 #

配置文件中引用配置文件，例在application.properties中：

local.ip=192.168.238.133
    local.port=8080
    my.address= ${
       local.ip}:${
       local.port}

得到的my.address得值就是：192.168.238.133:8080

# 五、获取集合、数组 #

配置方式：name\[index\] = value  
application.properties中配置：

ds.hosts[0]=192.168.238.130
    ds.hosts[1]=192.168.238.131
    ds.hosts[2]=192.168.238.132
    
    ds.ports[0]=8080
    ds.ports[1]=8081
    ds.ports[2]=8082

新建ClusterConfig.java ：

import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.stereotype.Component;
    
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;
    
    @Component
    @ConfigurationProperties("ds") // ds对应配置文件ds.hosts[0]等中的ds前缀
    public class ClusterConfig { 
    
        // 变量名对应配置文件ds.hosts[0]等中的 hosts
        private List<String> hosts = new ArrayList<>();
    
        // 变量名对应配置文件ds.ports[0]等中的 ports
        private Integer[] ports;
    
        public List<String> getHosts() {
            return hosts;
        }
    
        public void setHosts(List<String> hosts) {
            this.hosts = hosts;
        }
    
        public Integer[] getPorts() {
            return ports;
        }
    
        public void setPorts(Integer[] ports) {
            this.ports = ports;
        }
    
        @Override
        public String toString() {
            return "ClusterConfig{" +
                    "hosts=" + hosts +
                    ", ports=" + Arrays.toString(ports) +
                    '}';
        }
    }

App.java

import com.xh.config.ClusterConfig;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    @SpringBootApplication
    public class App {
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
            ClusterConfig clusterConfig = context.getBean(ClusterConfig.class);
            System.out.println(clusterConfig);
        }
    
    }

# 六、SpringBoot设置属性默认值 #

application.properties：

my.username=admin
    my.password=123456

#### 方法一：直接`@Value("${my.username:root}")` ####

#### 方法二： ####

App.java中

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    @SpringBootApplication
    public class App {
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
            // 如果没有该配置项，则返回defaultValue，如果有该配置项，则返回对应值
            String myUsername = context.getEnvironment().getProperty("my.username","root");
            System.out.println("myUsername = " + myUsername);
            String mysqlUsername = context.getEnvironment().getProperty("mysql.username","root");
            System.out.println("mysqlUsername = " + mysqlUsername);
        }
    
    }

控制台打印结果：

myUsername = admin
    mysqlUsername = root

#### 方法三：SpringApplication、map设定多个值 ####

在App.java中：

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    import java.util.HashMap;
    import java.util.Map;
    
    @SpringBootApplication
    public class App {
    
        public static void main(String[] args) {
            SpringApplication application = new SpringApplication(App.class);
            Map<String, Object> defaultMap = new HashMap<String, Object>();
            // 如果没有该配置项，则返回设定，如果有该配置项，则返回对应值
            defaultMap.put("my.username", "root");
            defaultMap.put("my.password", "111111");
            defaultMap.put("my.url", "jdbc:mysql://127.0.0.1:3306/test");
            defaultMap.put("my.username", "com.mysql.jdbc.Driver");
            // 还可以是Properties对象
            application.setDefaultProperties(defaultMap);
            ConfigurableApplicationContext context = application.run(args);
            System.out.println("my.username = " + context.getEnvironment().getProperty("my.username"));
            System.out.println("my.password = " + context.getEnvironment().getProperty("my.password"));
            System.out.println("my.url = " + context.getEnvironment().getProperty("my.url"));
            System.out.println("my.username = " + context.getEnvironment().getProperty("my.username"));
        }
    
    }

控制台打印结果：

my.username = admin
    my.password = 123456
    my.url = jdbc:mysql://127.0.0.1:3306/test
    my.username = admin