如何使用 setLogWriter 读取 DataSource 的日志流

Question

我需要能够查看使用数据库池的应用程序的查询日志。我发现 DataSource 允许我将 setLogWriter 与 PrintWriter 一起使用。

我必须处理将要输出的信息，所以我不想将它们发送到文件中。是否可以通过在流式传输时将其转换为字符串来从数据源读取信息流？

PoolProperties p = new PoolProperties();
        p.setUrl("jdbc:mysql://" + db_host + ":3306/" + db_name+"?logger=StandardLogger&profileSQL=true");

        p.setDriverClassName("com.mysql.jdbc.Driver");

        p.setUsername(db_user);
        p.setPassword(db_pwd);
        p.setJmxEnabled(true);
        //p.setTestWhileIdle(false);
        p.setTestOnBorrow(true);
        p.setValidationQuery("SELECT 1");
        p.setTestOnReturn(false);
        p.setValidationInterval(30000);
        p.setTimeBetweenEvictionRunsMillis(30000);
        p.setMaxActive(maxActive);
        p.setMaxIdle(5);
        p.setInitialSize(minActive);
        p.setMaxWait(30000);
        p.setRemoveAbandonedTimeout(300);
        p.setMinEvictableIdleTimeMillis(60000);
        p.setMinIdle(3);


        p.setLogAbandoned(true);
        p.setRemoveAbandoned(true);
        p.setJdbcInterceptors("org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;"
                + "org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer");
        ds = new DataSource();
        ds.setPoolProperties(p);
        ds.setLogWriter(new PrintWriter(...)); <-- Watch the output live of the PrintWriter

我想将 setLogWriter 重定向到 watch 函数，该函数将允许我在输出时将信息作为字符串读取和处理。示例：

Public void analyzeLog(String fromPrintWriter){
   if(fromPrintWriter.startsWith("abc"){
       CODE HERE... ETC
    }
}

Answer 1

在PipedWriter的帮助下和 PipedReader 你可以为读取日志输出做一个Reader。

适用于您的情况，代码可能与此类似：

ds = new DataSource();
ds.setPoolProperties(p);
PipedWriter pipedWriter = new PipedWriter();
ds.setLogWriter(new PrintWriter(pipedWriter));

Runnable runnable = () -> {
    // setup a Reader for reading the DataSource's log output
    try (BufferedReader bufferedReader = new BufferedReader(new PipedReader(pipedWriter))) {
        // start reading from PipedReader, so that writing to PipedWriter will not block
        String line = bufferedReader.readLine();
        while (line != null) {
            analyzeLog(line);
            line = bufferedReader.readLine();
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
};
new Thread(runnable).start();

Answer 2

给自己写一个 class 扩展 PrintWriter 并在执行代码后委托给另一个

如何使用 setLogWriter 读取 DataSource 的日志流

How can I read the log stream of a DataSource using setLogWriter

java

mysql

datasource