Springboot source code parsing: implements automatic spring boot configuration and spring boot source code

Springboot source code parsing: implements automatic spring boot configuration and spring boot source code

The last two articles show how to implement automatic spring boot configuration and condition annotation. Based on the previous two articles, this article implements automatic spring boot configuration and uses condition annotations.

Requirement: add your own handwritten jar. You can use StringRedisTemplate directly.

1. Create a maven project. pom. xml is as follows:

 
     
  
   4.0.0
      
  
   com.share1024
      redis    
  
   0.0.1-SNAPSHOT
      
  
   jar
      
  
   redis
      
  
   Demo project for Spring Boot
      
          
   
    org.springframework.boot
           spring-boot-starter-parent        
   
    1.5.10.RELEASE
           
    
        
   
      
          
   
    UTF-8
           
   
    UTF-8
           
   
    1.8
       
      
          
               
    
     org.springframework.boot
                spring-boot-starter        
           
               
    
     org.springframework.boot
                spring-boot-starter-data-redis        
           
               
    
     org.springframework.boot
                spring-boot-configuration-processor            
    
     true
            
       
  
 

Create RedisProperties. java class

package com.share1024;import org.springframework.boot.context.properties.ConfigurationProperties;/** * @author : yesheng * @Description : * @Date : 2018/2/26 */@ConfigurationProperties(prefix = "custom.redis")public class RedisProperties {    private int maxTotal;    private int maxIdle;    private long maxWait;    private String host;    private int port = 6379;    private int timeout;    public int getMaxTotal() {        return maxTotal;    }    public void setMaxTotal(int maxTotal) {        this.maxTotal = maxTotal;    }    public int getMaxIdle() {        return maxIdle;    }    public void setMaxIdle(int maxIdle) {        this.maxIdle = maxIdle;    }    public long getMaxWait() {        return maxWait;    }    public void setMaxWait(long maxWait) {        this.maxWait = maxWait;    }    public String getHost() {        return host;    }    public void setHost(String host) {        this.host = host;    }    public int getPort() {        return port;    }    public void setPort(int port) {        this.port = port;    }    public int getTimeout() {        return timeout;    }    public void setTimeout(int timeout) {        this.timeout = timeout;    }}

Here we use @ ConfigurationProperties (prefix = "custom. redis"), that is, the configuration in our application. yml/application. properties starts with custom. redis.
That is, convert properties to bean.

The configuration constant can be obtained using @ Value or Environment.

The constant configuration of redis has been written.

Create RedisAutoConfiguration. java class

package com.share1024;import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.boot.context.properties.EnableConfigurationProperties;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.core.env.Environment;import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.StringRedisTemplate;import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPoolConfig;/** * @author : yesheng * @Description : * @Date : 2018/2/26 */@Configuration@ConditionalOnClass({RedisTemplate.class, Jedis.class})@EnableConfigurationProperties(RedisProperties.class)@ConditionalOnProperty(prefix = "custom.redis",name = "host")public class RedisAutoConfiguration {    @Bean    public StringRedisTemplate stringRedisTemplate(JedisConnectionFactory jedisConnectionFactory){        StringRedisTemplate redisTemplate = new StringRedisTemplate();        redisTemplate.setConnectionFactory(jedisConnectionFactory);        return redisTemplate;    }    @Bean    public JedisPoolConfig jedisPoolConfig(RedisProperties redisProperties){        JedisPoolConfig poolConfig = new JedisPoolConfig();        if(redisProperties.getMaxTotal() !=0){            poolConfig.setMaxTotal(redisProperties.getMaxTotal());        }        if(redisProperties.getMaxIdle() !=0){            poolConfig.setMaxIdle(redisProperties.getMaxIdle());        }        if(redisProperties.getMaxWait()!=0){            poolConfig.setMaxWaitMillis(redisProperties.getMaxWait());        }        return poolConfig;    }    @Bean    public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig jedisPoolConfig,RedisProperties redisProperties){        JedisConnectionFactory jedisConnectionFactory  = new JedisConnectionFactory(jedisPoolConfig);        jedisConnectionFactory.setHostName(redisProperties.getHost());        jedisConnectionFactory.setPort(redisProperties.getPort());        if(redisProperties.getTimeout() !=0){            jedisConnectionFactory.setTimeout(redisProperties.getTimeout());        }        return jedisConnectionFactory;    }}

@ ConditionalOnClass ({RedisTemplate. class, Jedis. class })
To register this class to the container, you must find RedisTemplate. class and Jedis. class in the context of the project. Without these two classes, no configuration is made.

@ EnableConfigurationProperties (RedisProperties. class)
Make the @ ConfigurationProperties annotation take effect

@ ConditionalOnProperty (prefix = "custom. redis", name = "host ")
This is what we need in application. properties custom. redis. host.

The three @ beans in the file are used when the automatic configuration class meets the above @ ConditionalOnClass ({RedisTemplate. class, Jedis. class })
And @ ConditionalOnProperty (prefix = "custom. redis ", name =" host "), the class will be registered to the spring container, and all the @ beans under the class will be registered to the container.
In this way, we can directly use StringRedisTemplate

Create a META-INF/spring. factories in the resources Directory

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\com.share1024.RedisAutoConfiguration

The previous article explains how to use EnableAutoConfigurationImportSelector. class in @ EnableAutoConfiguration. Repeat the process.

ConfigurationClassPostProcessor goes back to scan @ Component in the lifecycle.

Then recursively scan @ ImportResource, @ PropertySource, @ ComponentScan, @ Bean, @ Import in the class. Processing is complete.

@ EnableAutoConfiguration
With @ Import (EnableAutoConfigurationImportSelector. class), The META-INF/spring. factories will be scanned
All org. springframework. boot. autoconfigure. EnableAutoConfiguration. For further scanning.

Complete.

mvn clean install

Create a new project. Introduce the package project

 @Autowired private StringRedisTemplate redisTemplate;

That's easy.

Most of the time we want to expand spring functions, we can also start from this direction. For example, Ctrip's apollo framework is also like this. If you are interested, you can study it.

Some time ago, springCloud finished its research and many people said that the source code could not be understood. I said it was very simple. What springcloud could not understand was springboot source code. Especially the first two articles. Have the opportunity to analyze the springcloud source code.