ResultSetConverter

SetLowerCaseFieldNames

Sets whether column names are converted to lowercase when used as keys or headers. Applies globally to all subsequent calls. Default is false.

• value — If true, all column names used as keys or headers are lowercased.

Example — SetLowerCaseFieldNames(false) (default):

[{"Name":"John", "Age":30, "HireDate":"2020-03-15"}, ...]

Example — SetLowerCaseFieldNames(true):

[{"name":"John", "age":30, "hiredate":"2020-03-15"}, ...]

All examples below use the following sample database table:

SQL Query used:

SELECT Name, Age, Salary, Active, HireDate FROM Employees

Returns a Map of column names to their JDBC type names. Useful for inspecting the schema of a ResultSet before processing it.

• rs — The ResultSet to inspect.

Output:

{
  "Name":     "VARCHAR",
  "Age":      "INTEGER",
  "Salary":   "DOUBLE",
  "Active":   "BOOLEAN",
  "HireDate": "DATE"
}

Returns a List of column names from the ResultSet.

• rs — The ResultSet to inspect.

Output:

["Name", "Age", "Salary", "Active", "HireDate"]

Converts the ResultSet into a List of Maps. Each row becomes a Map with column names as keys. If includeRowNumber is true, a 1-based row number is added as the first entry, using rowNumberColumnName as the key. Pass null for rowNumberColumnName to use the default key "Row".

• rs — The ResultSet to convert.
• includeRowNumber — If true, each Map includes a row number field.
• rowNumberColumnName — The key name for the row number field. Defaults to "Row" if null.

Output (includeRowNumber = false):

[
  {"Name": "John", "Age": 30, "Salary": 55000.5, "Active": true, "HireDate": "2020-03-15"},
  {"Name": "Jane", "Age": 25, "Salary": 48000.0, "Active": true, "HireDate": "2021-07-01"},
  {"Name": "Bob", "Age": 40, "Salary": 72000.75, "Active": false, "HireDate": "2018-11-20"}
]

Output (includeRowNumber = true, rowNumberColumnName = null):

[
  {"Row": 1, "Name": "John", "Age": 30, "Salary": 55000.5, "Active": true, "HireDate": "2020-03-15"},
  {"Row": 2, "Name": "Jane", "Age": 25, "Salary": 48000.0, "Active": true, "HireDate": "2021-07-01"},
  {"Row": 3, "Name": "Bob", "Age": 40, "Salary": 72000.75, "Active": false, "HireDate": "2018-11-20"}
]

Output (includeRowNumber = true, rowNumberColumnName = "#"):

[
  {"#": 1, "Name": "John", "Age": 30, "Salary": 55000.5, "Active": true, "HireDate": "2020-03-15"},
  {"#": 2, "Name": "Jane", "Age": 25, "Salary": 48000.0, "Active": true, "HireDate": "2021-07-01"},
  {"#": 3, "Name": "Bob", "Age": 40, "Salary": 72000.75, "Active": false, "HireDate": "2018-11-20"}
]

Converts the ResultSet into a List of Lists. If includeHeader is true, the first inner list contains the column names.

• rs — The ResultSet to convert.
• includeHeader — If true, the first List contains column names.

Output (includeHeader = true):

[
  ["Name",   "Age",    "Salary",     "Active",   "HireDate"],
  ["John",   30,       55000.5,      true,      "2020-03-15"],
  ["Jane",   25,       48000.0,      true,      "2021-07-01"],
  ["Bob",    40,       72000.75,     false,     "2018-11-20"]
]

Output (includeHeader = false):

[
  ["John",   30,   55000.5,    true,    "2020-03-15"],
  ["Jane",   25,   48000.0,    true,    "2021-07-01"],
  ["Bob",    40,   72000.75,   false,   "2018-11-20"]
]

Extracts values from the first column into a flat List. Expects a ResultSet with a single column.

• rs — The ResultSet to convert.

Output:

["John", "Jane", "Bob"]

Returns a single value from the first column of the first row. Ideal for aggregate queries such as COUNT(*), MAX(), SUM(), etc. Returns null if the ResultSet is empty.

• rs — The ResultSet to read.

Example 1 — SELECT COUNT(*) FROM Employees

3

Example 2 — SELECT MAX(Age) FROM Employees

40

Example 3 — SELECT SUM(Salary) FROM Employees

175001.25

Example 4 — SELECT Name FROM Employees WHERE Age = 30

"John"

Returns the first column of the first row as a String. Any column type is accepted: numeric, boolean, date, and string types are all converted via their toString representation. Dates are formatted as "yyyy-MM-dd", times as "HH:mm:ss", and timestamps as "yyyy-MM-dd'T'HH:mm:ss.SSSXXX". Returns null if the ResultSet is empty, the value is SQL NULL, or an error occurs.

• rs — The ResultSet to read.

Example — SELECT Name FROM Employees WHERE Age = 30

"John"

Example — SELECT Age FROM Employees WHERE Age = 30

"30"

Returns the first column of the first row as an int. Returns 0 if the ResultSet is empty, the value is SQL NULL, the column is not an integer type, or an error occurs.

Accepted column types: INTEGER, SMALLINT, TINYINT.

• rs — The ResultSet to read.

Example — SELECT Age FROM Employees WHERE Name = 'John'

30

Returns 0 if the column is not an integer type or the value is SQL NULL.

Returns the first column of the first row as a long. Returns 0 if the ResultSet is empty, the value is SQL NULL, the column is not a bigint type, or an error occurs.

Accepted column types: BIGINT.

• rs — The ResultSet to read.

Example — SELECT Id FROM Employees WHERE Name = 'John' (Id is BIGINT)

1001

Returns 0 if the column is not a bigint type or the value is SQL NULL.

Returns the first column of the first row as a double. Returns 0.0 if the ResultSet is empty, the value is SQL NULL, the column is not a floating-point or decimal type, or an error occurs.

Accepted column types: DOUBLE, FLOAT, REAL, DECIMAL, NUMERIC.

• rs — The ResultSet to read.

Example — SELECT Salary FROM Employees WHERE Name = 'John'

55000.5

Returns 0.0 if the column is not a numeric type or the value is SQL NULL.

Converts a single-row ResultSet into a Map with column names as keys. If more than one row exists, only the first row is used.

• rs — The ResultSet to convert.

Output:

{
  "Name":     "John",
  "Age":      30,
  "Salary":   55000.5,
  "Active":   true,
  "HireDate": "2020-03-15"
}

Converts the ResultSet into a Map of Maps. The first column's value is used as the key for each row. Column one should contain unique values.

• rs — The ResultSet to convert.

Output:

{
  "John": {
    "Name": "John", "Age": 30, "Salary": 55000.5,
    "Active": true, "HireDate": "2020-03-15"
  },
  "Jane": {
    "Name": "Jane", "Age": 25, "Salary": 48000.0,
    "Active": true, "HireDate": "2021-07-01"
  },
  "Bob": {
    "Name": "Bob", "Age": 40, "Salary": 72000.75,
    "Active": false, "HireDate": "2018-11-20"
  }
}

Converts the ResultSet into a column-oriented Map. Each key is a column name, and each value is a List of all values in that column.

• rs — The ResultSet to convert.

Output:

{
  "Name":     ["John",       "Jane",       "Bob"],
  "Age":      [30,           25,           40],
  "Salary":   [55000.5,      48000.0,      72000.75],
  "Active":   [true,         true,         false],
  "HireDate": ["2020-03-15", "2021-07-01", "2018-11-20"]
}

Converts a single-column ResultSet into a Map with the row number (starting at 1) as the key and the column value as the value.

• rs — The ResultSet to convert.

Output:

{
  1: "John",
  2: "Jane",
  3: "Bob"
}

Converts a two-column ResultSet into a Map. The first column provides the keys and the second column provides the values.

• rs — The ResultSet to convert.

Output:

{
  "John": 30,
  "Jane": 25,
  "Bob":  40
}

Converts the ResultSet to a JSON array of objects, with column names as keys. If includeRowNumber is true, each object includes a "Row" field (1-based) as the first key.

• rs — The ResultSet to convert.
• includeRowNumber — If true, each object includes a "Row" field.

Output (includeRowNumber = false):

[
  {"Name":"John","Age":30,"Salary":55000.5,"Active":true,"HireDate":"2020-03-15"},
  {"Name":"Jane","Age":25,"Salary":48000.0,"Active":true,"HireDate":"2021-07-01"},
  {"Name":"Bob","Age":40,"Salary":72000.75,"Active":false,"HireDate":"2018-11-20"}
]

Output (includeRowNumber = true):

[
  {"Row":1,"Name":"John","Age":30,"Salary":55000.5,"Active":true,"HireDate":"2020-03-15"},
  {"Row":2,"Name":"Jane","Age":25,"Salary":48000.0,"Active":true,"HireDate":"2021-07-01"},
  {"Row":3,"Name":"Bob","Age":40,"Salary":72000.75,"Active":false,"HireDate":"2018-11-20"}
]

Converts the first row of the ResultSet to a single JSON object with column names as keys. Returns {} if the ResultSet is empty. If more than one row exists, only the first is used.

• rs — The ResultSet to convert.

Output:

{"Name":"John","Age":30,"Salary":55000.5,"Active":true,"HireDate":"2020-03-15"}

Converts the first column of the ResultSet to a flat JSON array. Expects a single-column ResultSet.

• rs — The ResultSet to convert.

Output:

["John","Jane","Bob"]

Converts the ResultSet to an ECharts-compatible time-series JSON object. The time column must contain epoch millisecond values stored as a BIGINT. Each name in valueColumns produces one series in the output. Column lookup for both timeColumn and valueColumns is case-insensitive.

• rs — The ResultSet to convert.
• timeColumn — Column name containing epoch-ms timestamps (BIGINT).
• valueColumns — Column names to expose as series (case-insensitive).

Output — ToTimeSeriesJSON(rs, "Ts", Array("CPU", "Memory")):

{"series":[
  {"name":"CPU","data":[
    [1711450000000,23.4],
    [1711450060000,41.7],
    [1711450120000,35.1]
  ]},
  {"name":"Memory","data":[
    [1711450000000,61.2],
    [1711450060000,63.8],
    [1711450120000,62.5]
  ]}
]}

Converts the ResultSet to a paginated JSON object. All rows are read into memory first, then the requested page slice is returned. Pages are 1-based. If page is less than 1 it is clamped to 1; if pageSize is less than 1 it defaults to 100.

Respects SetLowerCaseFieldNames.

• rs — The ResultSet to convert.
• page — 1-based page number to return.
• pageSize — Number of rows per page.

Output — ToPagedJSON(rs, 1, 2) on the Employees table:

{
  "page":      1,
  "pageSize":  2,
  "totalRows": 3,
  "data": [
    {"Name":"John","Age":30,"Salary":55000.5,"Active":true,"HireDate":"2020-03-15"},
    {"Name":"Jane","Age":25,"Salary":48000.0,"Active":true,"HireDate":"2021-07-01"}
  ]
}

Page 2 of the same query — ToPagedJSON(rs, 2, 2):

{
  "page":      2,
  "pageSize":  2,
  "totalRows": 3,
  "data": [
    {"Name":"Bob","Age":40,"Salary":72000.75,"Active":false,"HireDate":"2018-11-20"}
  ]
}

Converts the ResultSet to a CSV string. Lines are separated by CRLF per RFC 4180. Values containing commas, double-quotes, or newlines are wrapped in double-quotes, with internal double-quotes escaped by doubling.

• rs — The ResultSet to convert.
• includeHeader — If true, the first line contains column names.

Output (includeHeader = true):

Name,Age,Salary,Active,HireDate
John,30,55000.5,true,2020-03-15
Jane,25,48000.0,true,2021-07-01
Bob,40,72000.75,false,2018-11-20

Output (includeHeader = false):

John,30,55000.5,true,2020-03-15
Jane,25,48000.0,true,2021-07-01
Bob,40,72000.75,false,2018-11-20

Converts the ResultSet to an HTML table string with <thead> and <tbody> sections. Column names are used as header cells. All text content is HTML-escaped. Null values render as empty cells.

• rs — The ResultSet to convert.
• cssClass — Optional CSS class for the <table> element. Pass null or "" for no class.

Output (cssClass = "data-table"):

<table class="data-table">
  <thead><tr><th>Name</th><th>Age</th><th>Salary</th><th>Active</th><th>HireDate</th></tr></thead>
  <tbody>
    <tr><td>John</td><td>30</td><td>55000.5</td><td>true</td><td>2020-03-15</td></tr>
    <tr><td>Jane</td><td>25</td><td>48000.0</td><td>true</td><td>2021-07-01</td></tr>
    <tr><td>Bob</td><td>40</td><td>72000.75</td><td>false</td><td>2018-11-20</td></tr>
  </tbody>
</table>

The following table shows how JDBC types are mapped to Java types when reading values from a ResultSet: