springboot 使用yml配置文件给静态变量赋值教程

声明：

此处需求是修改封装的clickhouseUtil数据查询引擎连接工具类。由于此类中的方法都是静态方法。连接地址等参数需要根据不同环境改变。例如开发下地址，测试下地址，生产地址等，所有通过配置文件来获取不同环境下的配置参数，但是使用的方法是静态的，所有不能使用一般情况下的@value直接给变量赋值，需要用到spring 属性的set方法来给静态变量赋值，然后静态方法使用静态变量即可

方法：

第一步：在yml文件中配置需要的参数

clickhouse:
 address: jdbc:clickhouse://172.20.xxx.xxx:8123
 username: default
 password: xxxxx
 db: marketing
 socketTimeout: 600000

第二步：

类上一定要先注明@Component注解，在程序启动是自动加载，否则静态参数仍旧获取不到配置文件的值

创建静态变量

给静态变量set方法上添加@Value()

 @Value("${clickhouse.address}")
 public void setClickhouseAddress(String address) {
  ClickHouseUtil.clickhouseAddress = address;
 }

最后在静态方法中使用即可

@Component
public class ClickHouseUtil {

 private static String clickhouseAddress;

 private static String clickhouseUsername;

 private static String clickhousePassword;

 private static String clickhouseDB;

 private static Integer clickhouseSocketTimeout;

 @Value("${clickhouse.address}")
 public void setClickhouseAddress(String address) {
  ClickHouseUtil.clickhouseAddress = address;
 }
 @Value("${clickhouse.username}")
 public void setClickhouseUsername(String username) {
  ClickHouseUtil.clickhouseUsername = username;
 }
 @Value("${clickhouse.password}")
 public void setClickhousePassword(String password) {
  ClickHouseUtil.clickhousePassword = password;
 }
 @Value("${clickhouse.db}")
 public void setClickhouseDB(String db) {
  ClickHouseUtil.clickhouseDB = db;
 }
 @Value("${clickhouse.socketTimeout}")
 public void setClickhouseSocketTimeout(Integer socketTimeout) {
  ClickHouseUtil.clickhouseSocketTimeout = socketTimeout;
 }

 public static Connection getConn() {

  ClickHouseConnection conn = null;
  ClickHouseProperties properties = new ClickHouseProperties();
  properties.setUser(clickhouseUsername);
  properties.setPassword(clickhousePassword);
  properties.setDatabase(clickhouseDB);
  properties.setSocketTimeout(clickhouseSocketTimeout);
  ClickHouseDataSource clickHouseDataSource = new ClickHouseDataSource(clickhouseAddress,properties);
  try {
   conn = clickHouseDataSource.getConnection();
   return conn;
  } catch (SQLException e) {
   e.printStackTrace();
  }

  return null;
 }

 public static List<JSONObject> exeSql(String sql){
  log.info("cliockhouse 执行sql：" + sql);
  Connection connection = getConn();
  try {
   Statement statement = connection.createStatement();
   ResultSet results = statement.executeQuery(sql);
   ResultSetMetaData rsmd = results.getMetaData();
   List<JSONObject> list = new ArrayList();
   while(results.next()){
    JSONObject row = new JSONObject();
    for(int i = 1;i<=rsmd.getColumnCount();i++){
     row.put(rsmd.getColumnName(i),results.getString(rsmd.getColumnName(i)));
    }
    list.add(row);
   }

   return list;
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return null;
 }

}

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