How to Populate JFreeChart TimeSeriesCollection from MySQL DB with Accurate Time Values?

How to Populate JFreeChart TimeSeriesCollection from MySQL DB?

Introduction

JFreeChart TimeSeriesCollection is a data structure used to hold time series data for visualization in charts. When attempting to populate this collection from a MySQL database, challenges may arise in accurately displaying the data. Here's a detailed explanation of how to overcome these challenges and generate a correct chart:

Problem

In the given code, the issue lies in the conversion from String to Date. The code uses SimpleDateFormat to convert the result from the SQL query to a Date object. However, precision may be lost during this conversion, leading to incorrect display of time values in the chart.

Solution

To resolve this issue, the following steps are recommended:

1. Ensure that the MySQL database stores the datetime data in the correct format, preferably as a Timestamp or DateTime data type.
2. In the code, convert the String result from the SQL query to a Timestamp object using Timestamp.valueOf(stringDate).
3. Add the Timestamp object to the TimeSeries as a new data point using TimeSeries.addOrUpdate(timestamp, value).

By implementing these changes, the TimeSeriesCollection will accurately display the datetime values without loss of precision, resulting in a correct visualization of the time series data.

Additional Tips

• Use JDBCXYDataset: JDBCXYDataset is a specialized class in JFreeChart that is designed to connect to a database and retrieve time series data. It provides a simpler and more efficient way to populate the TimeSeriesCollection.
• Query Optimization: Optimize the SQL query to retrieve only the relevant data within the desired time range.
• Data Validation: Perform data validation before adding to the TimeSeriesCollection to ensure data integrity.
• Chart Customization: Customize the chart appearance, including axis labels, title, and plot style to enhance readability and visual appeal.

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