Background
在開發中可能會有這樣的情景。需要在容器啓動的時候執行一些內容。比如讀取配置文件,數據庫連接之類的。SpringBoot給我們提供了兩個接口來幫助我們實現這種需求。這兩個接口分別爲
CommandLineRunner
和ApplicationRunner
。他們的執行時機爲容器啓動完成的時候。
這兩個接口中有一個run方法,我們只需要實現這個方法即可。這兩個接口的不同之處在於:ApplicationRunner中run方法的參數爲ApplicationArguments,而CommandLineRunner接口中run方法的參數爲String數組。
ApplicationRunner
在容器啓動時把數據庫中的基本信息加載到內存中
package com.cloudansys.monitor.common;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
@Slf4j
@Component
public class CacheHandler implements ApplicationRunner {
@Autowired
private JdbcTemplate jdbcTemplate;
// 每個 targetId 對應的參數的codes
private Map<Integer, List<Integer>> paramCodes = new ConcurrentHashMap<>();
// 每個 targetId 對應的參數的names
private Map<Integer, List<String>> paramNames = new ConcurrentHashMap<>();
// 每個 targetId 的 targetCode
private Map<Integer, String> targetsCode = new ConcurrentHashMap<>();
public List<String> getParamCodes(Integer targetId) {
List<Integer> codes = this.paramCodes.get(targetId);
List<String> list = new ArrayList<>();
for (Integer code : codes) {
list.add(String.valueOf(code));
}
return list;
}
public List<String> getParamNames(Integer targetId) {
return this.paramNames.get(targetId);
}
public String getTargetCode(Integer targetId) {
return this.targetsCode.get(targetId);
}
@Override
public void run(ApplicationArguments args) throws Exception {
final String SQL_1 = "SELECT id FROM %s ;";
final String SQL_2 = "SELECT type FROM %s WHERE id = ? ;";
final String SQL_3 = "SELECT code FROM %s WHERE target_type = ? ;";
final String SQL_4 = "SELECT name FROM %s WHERE target_type = ? ;";
final String SQL_5 = "SELECT code as targetCode FROM %s WHERE id = ?;";
final String sql_1 = String.format(SQL_1, Constants.DB.TARGET_INFO);
final String sql_2 = String.format(SQL_2, Constants.DB.TARGET_INFO);
final String sql_3 = String.format(SQL_3, Constants.DB.QUOTA_INFO);
final String sql_4 = String.format(SQL_4, Constants.DB.QUOTA_INFO);
final String sql_5 = String.format(SQL_5, Constants.DB.TARGET_INFO);
// log.debug("sql_1: {}", sql_1);
// log.debug("sql_2: {}", sql_2);
// log.debug("sql_3: {}", sql_3);
// log.debug("sql_4: {}", sql_4);
// log.debug("sql_5: {}", sql_5);
// 獲取所有的測點 id
final List<Integer> ids = this.jdbcTemplate.queryForList(sql_1, Integer.class);
// 遍歷 ids 獲取每個測點 id 對應的 測點編號 targetCode、參數名 paramNames、參數編號 codeNames
for (Integer id : ids) {
// 獲取測點 id 對應的類型,且每個測點 id 只有一個類型
final List<String> types = this.jdbcTemplate.queryForList(sql_2, String.class, id);
Integer type = Integer.valueOf(types.get(0));
// 獲取測點 id 對應的測點編號,並把所有 id 和 targetCode 的對應關係放到 targetsCode Map 中
String targetCode = this.jdbcTemplate.queryForList(sql_5, String.class, id).get(0);
this.targetsCode.put(id, targetCode);
// 獲取測點 id 對應類型中包含的參數編號,並根據參數編號獲取參數名
final List<Integer> paramCodes = this.jdbcTemplate.queryForList(sql_3, Integer.class, type);
final List<String> paramNames = this.jdbcTemplate.queryForList(sql_4, String.class, type);
this.paramCodes.put(id, paramCodes);
this.paramNames.put(id, paramNames);
}
}
}
CommandLineRunner
這是個定時任務,且在容器啓動時加載,定時向mqtt發送消息
package com.cloudansys.processor;
import com.cloudansys.config.MqttGateway;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.util.List;
import java.util.Map;
@Slf4j
@Component
@EnableScheduling
public class ProcessorEMQ implements Processor, CommandLineRunner {
private ObjectMapper objectMapper;
@Autowired
private MqttGateway gateway;
private static final String SEND_TOPIC = "warn_blast";
@Autowired
private JdbcTemplate jdbcTemplate;
public ProcessorEMQ(){
this.objectMapper = new ObjectMapper();
}
@Override
public void run(String... args) {
exec();
}
// {秒} {分} {時} {日} {月} {星期} {年份(可爲空)}
// @Scheduled(cron = "10 * * * * ?", zone = "GMT+8")
@Scheduled(cron = "*/10 * * * * ?")
private void exec() {
String sql = "SELECT node_id, time_o, `value` FROM simulation_data_blast WHERE id = ?;";
log.debug("sql :{} ", sql);
int num = (int) (Math.random() * 1000);
log.info("num: {}", num);
Object args[] = {num};
List<Map<String, Object>> maps = this.jdbcTemplate.queryForList(sql, args);
maps.forEach(System.out::println);
try {
String payload = this.objectMapper.writeValueAsString(maps);
log.info("payload: {}", payload);
this.gateway.sendToMqtt(SEND_TOPIC, payload);
} catch (IOException e) {
e.printStackTrace();
}
}
}