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Spring Boot读取配置文件与优先级 详解Spring Boot读取配置文件与配置文件优先级

良辰美景TT 人气:0

Spring Boot读取配置文件

1)通过注入ApplicationContext 或者 Environment对象来读取配置文件里的配置信息。

package com.ivan.config.controller;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.core.env.Environment;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class ConfigController {
  @Autowired

  ApplicationContext context;

  @Autowired

  Environment environment;

  @RequestMapping(value="/config", method={RequestMethod.GET})

  public String getConfigContent(){       

    String name = context.getEnvironment().getProperty("db.user.name");

    return name;

  }

  @RequestMapping(value="/configEnv", method={RequestMethod.GET})

  public String getConfigEnvironment(){

    String name = environment.getProperty("db.user.name");

    return name;

  }
}

2)通过@ConfigurationProperties配合@PropertySource读取配置文件里的配置信息。

1:通过@PropertySource指定当前类里属性的配置文件地址,ConfigurationProperties可以指定配置的前缀,@Configuration用于定义一个配置类:

package com.ivan.config.entity;
import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.PropertySource;

@Configuration

@PropertySource("classpath:config/druid.properties")

@ConfigurationProperties(prefix = "druid")

public class DruidConfig {

  private int  initialSize;

  private int  minIdle;

  private int  maxActive;

  private int  maxWait;

  private String validationQuery;

  private boolean testWhileIdle;

  private boolean testOnBorrow;

  private boolean testOnReturn;

  public int getInitialSize() {

    return initialSize;

  }

  public void setInitialSize(int initialSize) {

    this.initialSize = initialSize;

  }

  public int getMinIdle() {

    return minIdle;

  }

  public void setMinIdle(int minIdle) {

    this.minIdle = minIdle;

  }

  public int getMaxActive() {

    return maxActive;

  }

  public void setMaxActive(int maxActive) {

    this.maxActive = maxActive;

  }

  public int getMaxWait() {

    return maxWait;

  }

  public void setMaxWait(int maxWait) {

    this.maxWait = maxWait;

  }

  public String getValidationQuery() {

    return validationQuery;

  }

  public void setValidationQuery(String validationQuery) {

    this.validationQuery = validationQuery;

  }

  public boolean isTestWhileIdle() {

    return testWhileIdle;

  }

  public void setTestWhileIdle(boolean testWhileIdle) {

    this.testWhileIdle = testWhileIdle;

  }

  public boolean isTestOnBorrow() {

    return testOnBorrow;

  }

  public void setTestOnBorrow(boolean testOnBorrow) {

    this.testOnBorrow = testOnBorrow;

  }

  public boolean isTestOnReturn() {

    return testOnReturn;

  }

  public void setTestOnReturn(boolean testOnReturn) {

    this.testOnReturn = testOnReturn;

  }

  @Override

  public String toString() {

    return "DruidConfig [initialSize=" + initialSize + ", minIdle=" + minIdle + ", maxActive=" + maxActive + ", maxWait=" + maxWait + ", validationQuery=" + validationQuery + ", testWhileIdle=" + testWhileIdle + ", testOnBorrow=" + testOnBorrow + ", testOnReturn=" + testOnReturn + "]";

  }
}

2:对应的配置文件:

druid.initialSize=5
druid.minIdle=5
druid.maxActive=20
druid.maxWait=60000
druid.validationQuery=select 'x'
druid.testWhileIdle=true 
druid.testOnBorrow=true 
druid.testOnReturn=true

3:在需要用到的类通过@Autowired注入

package com.ivan.config.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import com.ivan.config.entity.DruidConfig;
@RestController
public class DruidConfigController {
  @Autowired
  public DruidConfig druidConfig;

  @RequestMapping(value="/druidConfig", method={RequestMethod.GET})
  public String getDruidConfig(){
    return druidConfig.toString();
  }
}

3)通过@Value注解

1:需要得到配置属性的类如下,可以在任何需要得到配置的地方用@Value注解

package com.ivan.config.entity;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
@Configuration

public class ValueTest {
  @Value("${db.user.name}")
  private String username;
  public String getUsername() {
    return username;
  }
  public void setUsername(String username) {
    this.username = username;
  }
}

2:测试Controller类通过@Autowired注入实体类

package com.ivan.config.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import com.ivan.config.entity.ValueTest;
@RestController
public class ValueController {
  @Autowired
  private ValueTest value;

  @RequestMapping(value="/configValue", method={RequestMethod.GET})
  public String getConfig(){
    return value.getUsername();
  }
}

Spring boot 配置文件优先级:

1:命令行参数。(以--开头的参数,比如可以设置:--server.port对同一套代码设置不同的参数)
2: 通过 System.getProperties() 获取的 Java 系统参数。
3:操作系统环境变量(这解释了为什么你通过application.properties设置的user.name取的是系统的用户名了)
4:从 java:comp/env 得到的 JNDI 属性。
5: 应用 Jar 文件之外的属性文件(系统的application.properties文件)
6:应用 Jar 文件内部的属性文件。
7: 在应用配置 Java 类(包含“@Configuration”注解的 Java 类)中通过“@PropertySource”注解声明的属性文件。
8: 通过“SpringApplication.setDefaultProperties”声明的默认属性。

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