遇到了单独使用SqlServer连接池的情况，记录一下。

1. pom.xml依赖

  <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <!-- 本身不含连接池 -->
        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>sqljdbc4</artifactId>
            <version>4.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.zaxxer/HikariCP -->
        <dependency>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
            <version>3.4.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

2. 配置文件

app.sqlConn=jdbc:sqlserver://127.0.0.1:1433;databaseName=test
app.sqlUser=sa
app.sqlPwd=123456

3. 数据库连接工厂类

//读取配置文件的配置
@Data
@Configuration
@ConfigurationProperties(prefix = "app")
public class AppConfig {
    /**
     * SQL Server连接
     */
    private String sqlConn;

    /**
     * SQL Server用户名
     */
    private String sqlUser;

    /**
     * SQL Server密码
     */
    private String sqlPwd;
}

@Slf4j
@Component
public final class DBFactory {
    private static HikariDataSource INSTANCE = null;

    //数据库连接信息
    public static String URL;
    private static String USER_NAME  ;
    private static String PASSWORD  ;

    @Autowired
    private  AppConfig appConfig;

    //私有化，防止直接实例化
    private DBFactory() {
    }

    @PostConstruct
    public void init(){
        URL = appConfig.getSqlConn();
        USER_NAME = appConfig.getSqlUser();
        PASSWORD = appConfig.getSqlPwd();
    }


    /**
     * 获取数据源
     * 1. HikariDataSource提供的方法比DataSource丰富
     * 2. 保证多线程下单例
     *
     * @return
     */
    private static HikariDataSource getDataSource() {
        if (INSTANCE == null) {
            synchronized (DBFactory.class) {
                if (INSTANCE == null) {
                    HikariConfig config = new HikariConfig();
                    //最大连接数限制
                    config.setMaximumPoolSize(2000);
                    //写死driverClass，避免重复确认
                    config.setDataSourceClassName("com.microsoft.sqlserver.jdbc.SQLServerDataSource");
                    config.addDataSourceProperty("url", URL);
                    config.addDataSourceProperty("user", USER_NAME);
                    config.addDataSourceProperty("password", PASSWORD);
                    //TODO SqlServer没有找到cachePrepStmtpreStmtCacheSize相关的参数

                    INSTANCE = new HikariDataSource(config);
                }
            }
        }

        return INSTANCE;
    }

    /**
     * 获取数据库连接
     * @return
     */
    public static Connection getConnection() throws SQLException {
        if(getDataSource() == null){
            throw new RuntimeException("get sqlserver datasource failed");
        }
        return getDataSource().getConnection();
    }
    /**
     * 【慎用】
     */
    public static final void close() {
        if (INSTANCE != null) {
            // 检查多线程下其他客户端方法关闭
            synchronized (DBFactory.class) {
                if (INSTANCE != null) {
                    INSTANCE.close();
                    log.info("#########connection pool closed##########");
                }
            }
        }
    }
}

4. 使用

 public static void  insertUser(User user) throws SQLException {
        try (
                Connection conn = DBFactory.getConnection();
                Statement st = conn.createStatement();
        ) {
            String insertSQL = "Insert into user(id, name) VALUES(";
            insertSQL += user.getUser() + ", '";
            insertSQL += user.getName  + "'";
            insertSQL += ")";
            log.error(insertSQL);
            st.executeUpdate(insertSQL);
        } catch (Exception ex) {
            log.error("insert OA_RCT_ResumeEduEntityTags error: " + ex.getMessage());
            ex.printStackTrace();
        }
    }