日常积累
1.日期相关操作。
1.1字符串转Date类型
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public class Demo { |
1.2常用注解
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@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
2.java8相关操作
2.1过滤后进行排序操作
注：一个stream进行filter操作后，可以继续调用.collect(Collectors.groupingBy())，但是groupingBy里无法传入lambda表达式？
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9public JSONObject obtainOnlineJson(List
deviceDetailList){
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
StreamdataStream = deviceDetailList.stream()
.filter(data -> sdf.format(new Date()).equals(data.getGmtOnline().substring(0, 10)));
Map
JSONObject online = new JSONObject();
online.put(sdf.format(new Date()),onlineMap.size());
return online;
}
3.Map相关操作
3.1遍历map相关操作
四种方法：
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49import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
public class TestMap {
public static void main(String[] args) {
Map
map.put(1, "a");
map.put(2, "b");
map.put(3, "ab");
map.put(4, "ab");
map.put(4, "ab");// 和上面相同 ， 会自己筛选
System.out.println(map.size());
// 第一种：
/*
* Setset = map.keySet(); //得到所有key的集合
*
* for (Integer in : set) { String str = map.get(in);
* System.out.println(in + " " + str); }
*/
System.out.println("第一种：通过Map.keySet遍历key和value：");
for (Integer in : map.keySet()) {
//map.keySet()返回的是所有key的值
String str = map.get(in);//得到每个key多对用value的值
System.out.println(in + " " + str);
}
// 第二种：
System.out.println("第二种：通过Map.entrySet使用iterator遍历key和value：");
Iterator
while (it.hasNext()) {
Map.Entry
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
// 第三种：推荐，尤其是容量大时
System.out.println("第三种：通过Map.entrySet遍历key和value");
for (Map.Entry
//Map.entry
//entry.getKey() ;entry.getValue(); entry.setValue();
//map.entrySet() 返回此映射中包含的映射关系的 Set视图。
System.out.println("key= " + entry.getKey() + " and value= "
+ entry.getValue());
}
// 第四种：
System.out.println("第四种：通过Map.values()遍历所有的value，但不能遍历key");
for (String v : map.values()) {
System.out.println("value= " + v);
}
}
}
4.nginx使用记录
4.1安装与测试
添加资源库。
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vim /etc/yum.repos.d/nginx.repo（可以直接使用该命令，文件不存在会自动生成的。）
向第一步打开的nginx.repo文件写入以下内容。
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5[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1yum命令安装nginx。
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53yum install nginx
可以看到以下内容：
Loaded plugins: fastestmirror, langpacks
nginx | 2.9 kB 00:00
nginx/7/x86_64/primary_db | 14 kB 00:01
Loading mirror speeds from cached hostfile
* base: mirrors.sina.cn
* extras: mirrors.btte.net
* updates: mirrors.sina.cn
Resolving Dependencies
--> Running transaction check
---> Package nginx.x86_64 1:1.10.1-1.el7.ngx will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
nginx x86_64 1:1.10.1-1.el7.ngx nginx 640 k
Transaction Summary
================================================================================
Install 1 Package
Total download size: 640 k
Installed size: 2.1 M
Is this ok [y/d/N]: y
Downloading packages:
nginx-1.10.1-1.el7.ngx.x86_64.rpm | 640 kB 00:27
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : 1:nginx-1.10.1-1.el7.ngx.x86_64 1/1
----------------------------------------------------------------------
Thanks for using nginx!
Please find the official documentation for nginx here:
* http://nginx.org/en/docs/
Commercial subscriptions for nginx are available on:
* http://nginx.com/products/
----------------------------------------------------------------------
Verifying : 1:nginx-1.10.1-1.el7.ngx.x86_64 1/1
Installed:
nginx.x86_64 1:1.10.1-1.el7.ngx
Complete!测试nginx配置文件并查看安装的路径。
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4nginx -t
可以看到：
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful启动nginx。
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systemctl start nginx.service(无返回内容)
关闭防火墙。
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systemctl stop firewalld.service
在浏览器输入nginx安装在宿主机的ip地址，返回welcome nginx则大功告成。
5.redis使用记录
5.1redis多数据源配置
配置application.yml文件的redis
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28spring:
datasource:
url: jdbc:mysql://localhost/service?useUnicode=true&characterEncoding=utf-8&useSSL=false
username: ******
password: ******
redis:
host: ******
password: ******
redis-c40:
host: ******
password: ******
port: 6379
database: 0
redis-c51:
host: ******
password: ******
port: 6379
database: 1
redis-c53:
host: ******
password: ******
port: 6379
database: 2
pool:
max-active: 8
max-idle: 8
min-idle: 0
max-wait: 10000在config包下新建MultiRedisConfig.java。内容如下：
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95package com.uaes.iot.hub.config;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import redis.clients.jedis.JedisPoolConfig;
@Configuration
public class MultiRedisConfig {
@Value("${spring.pool.max-idle}")
private int maxIdle;
@Value("${spring.pool.max-active}")
private int maxActive;
@Value("${spring.pool.max-wait}")
private Long maxWait;
@Value("${spring.pool.min-idle}")
private int minIdle;
@Bean(name = "redisTemplateForC40")
public RedisTemplate
@Value("${spring.redis-c40.port}")int port,
@Value("${spring.redis-c40.password}")String password,
@Value("${spring.redis-c40.database}")int database) {
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = jackson2JsonRedisSerializer();
return redisTemplate(hostName,port,password,database,jackson2JsonRedisSerializer);
}
@Bean(name = "redisTemplateForC51")
public RedisTemplate
@Value("${spring.redis-c51.port}")int port,
@Value("${spring.redis-c51.password}")String password,
@Value("${spring.redis-c51.database}")int database) {
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = jackson2JsonRedisSerializer();
return redisTemplate(hostName,port,password,database,jackson2JsonRedisSerializer);
}
@Bean(name = "redisTemplateForC53")
public RedisTemplate
@Value("${spring.redis-c53.port}")int port,
@Value("${spring.redis-c53.password}")String password,
@Value("${spring.redis-c53.database}")int database) {
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = jackson2JsonRedisSerializer();
return redisTemplate(hostName,port,password,database,jackson2JsonRedisSerializer);
}
public Jackson2JsonRedisSerializer jackson2JsonRedisSerializer(){
Jackson2JsonRedisSerializer
ObjectMapper om = new ObjectMapper();
om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
jackson2JsonRedisSerializer.setObjectMapper(om);
return jackson2JsonRedisSerializer;
}
public RedisConnectionFactory connectionFactory(
String hostName, int port, String password, int maxIdle,int minIdle, int maxTotal, int index, long maxWaitMillis) {
JedisConnectionFactory jedis = new JedisConnectionFactory();
jedis.setHostName(hostName);
jedis.setPort(port);
jedis.setPassword(password);
jedis.setDatabase(index);
jedis.setPoolConfig(this.poolConfig(maxIdle,minIdle, maxTotal, maxWaitMillis));
jedis.afterPropertiesSet();
RedisConnectionFactory factory = jedis;
return factory;
}
public RedisTemplate
RedisTemplate
template.setConnectionFactory(this.connectionFactory(
hostName, port, password, maxIdle, minIdle,maxActive,database,maxWait));
template.setKeySerializer(jackson2JsonRedisSerializer);
template.setValueSerializer(jackson2JsonRedisSerializer);
template.setHashKeySerializer(jackson2JsonRedisSerializer);
template.setHashValueSerializer(jackson2JsonRedisSerializer);
template.afterPropertiesSet();
return template;
}
public JedisPoolConfig poolConfig(int maxIdle, int minIdle,int maxActive, long maxWaitMillis) {
JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxIdle(maxIdle);
poolConfig.setMinIdle(minIdle);
poolConfig.setMaxTotal(maxActive);
poolConfig.setMaxWaitMillis(maxWaitMillis);
poolConfig.setTestOnBorrow(false);
return poolConfig;
}
}新建测试类进行测试。
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37package com.uaes.iot.hub.service.device;
import com.uaes.iot.hub.HubApplication;
import com.uaes.iot.hub.domain.CarCurrent;
import com.uaes.iot.hub.service.car.CarCurrentService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.test.context.junit4.SpringRunner;
/**
* Created by xk on 2017/12/14.
*/
@RunWith(SpringRunner.class)
@SpringBootTest(classes = HubApplication.class)
public class CarCurrentServiceTest {
@Autowired
private CarCurrentService carCurrentService;
@Autowired
private RedisTemplate redisTemplateForC40;
@Autowired
private RedisTemplate redisTemplateForC51;
@Autowired
private RedisTemplate redisTemplateForC53;
@Test
public void testMultiRedis(){
Object test1 = redisTemplateForC40.opsForHash().get(CarCurrent.OBJECT_KEY, "LNBSCCAK4JT100137");
Object test2 = redisTemplateForC51.opsForHash().get(CarCurrent.OBJECT_KEY, "LNBSCCAK4JT100137");
Object test3 = redisTemplateForC53.opsForHash().get(CarCurrent.OBJECT_KEY, "LNBSCCAK4JT100137");
System.out.println(test1);
System.out.println(test2);
System.out.println(test3);
}
}总结：
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161. 可以在MultiRedisConfig类的每个@Bean方法打个断点，会发现每个redisTemplate的连接信息不同。
2. 测试类里可以通过断点发现的确是从每个redis的不同DB取值。
3. 注意redis序列化问题，在MultiRedisConfig的redisTemplate()方法里设置不同的序列化。也可以这样设置序列化（默认的redisTemplate使用的就是这个序列化）：
public RedisTemplate
RedisTemplate
temple.setConnectionFactory(this.connectionFactory(
hostName, port, password, maxIdle, maxTotal, index, maxWaitMillis));
RedisSerializer stringSerializer = new StringRedisSerializer();
temple.setKeySerializer(stringSerializer);//key序列化
temple.setValueSerializer(jackson2JsonRedisSerializer);//value序列化
temple.setHashKeySerializer(stringSerializer);//Hash key序列化
temple.setHashValueSerializer(jackson2JsonRedisSerializer);//Hash value序列化
return temple;
}
5.2redis其他用法
6.Java中使用Kafka记录
6.1消费者使用
在pom.xml文件引入如下依赖：
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org.springframework.kafka
spring-kafka
1.1.4.RELEASE 在application.yml文件里配置连接Kafka的信息：
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3kafka:
topics: BAIC-C40D-M05-uaes-result-topic,BAIC-C51E-F05-uaes-result-topic,BAIC-C53F-uaes-result-topic
broker_list: ******,******,******在config包下新建KafkaConsumerConfig类，内容如下：
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53package com.uaes.iot.emr.kafka.config;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.config.KafkaListenerContainerFactory;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
import org.springframework.kafka.listener.ConcurrentMessageListenerContainer;
import java.util.HashMap;
import java.util.Map;
/**
* Created by xk on 2018/05/22
*/
@Configuration
@EnableKafka
public class KafkaConsumerConfig {
@Value("${kafka.broker_list}")
private String services;
public Map
Map
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, services);
props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
props.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "100");
props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, "15000");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.GROUP_ID_CONFIG, "multi-tenancy");
return props;
}
public ConsumerFactory
return new DefaultKafkaConsumerFactory<>(consumerConfigs());
}
@Bean
public KafkaListenerContainerFactory
ConcurrentKafkaListenerContainerFactory
factory.setConsumerFactory(consumerFactory());
factory.setConcurrency(3);
factory.getContainerProperties().setPollTimeout(3000);
return factory;
}
}在process.in包下新建KafkaConsumerService类，内容如下：
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37package com.uaes.iot.emr.kafka.process.in;
import com.iot.util.ReturnData;
import com.uaes.iot.emr.kafka.client.*;
import com.uaes.iot.emr.kafka.common.PushParaPost;
import com.uaes.iot.emr.kafka.dto.*;
import net.sf.json.JSONObject;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.ResponseEntity;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Map;
/**
* Created by xk on 2018/05/22
*/
@Component
public class KafkaConsumerService {
@KafkaListener(topics = {"#{'${kafka.topics}'.split(',')}"})
public void consumerEmrKafkaMessage(ConsumerRecord record){
JSONObject message = JSONObject.fromObject(record.value());
String topic = record.topic();
if (message == null || StringUtils.isEmpty(message)) {
return;
}
Logger logger = LoggerFactory.getLogger(KafkaConsumerService.class);
logger.info("获取到数据了："+message.get("data"));
}
}总结：
- @KafkaListener(topics = {“#{‘${kafka.topics}’.split(‘,’)}”})这种写法以后如果需要在监听其他topic时，只需要在application.yml文件里添加即可。
6.2生产者使用
-