docs.sheetjs.com/docz/docs/03-demos/42-engines/07-nashorn.md

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---
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title: Data Processing with Nashorn
sidebar_label: Java + Nashorn
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pagination_prev: demos/bigdata/index
pagination_next: solutions/input
---
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import current from '/version.js';
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import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';
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import CodeBlock from '@theme/CodeBlock';
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[Nashorn](https://openjdk.org/projects/nashorn/) is a JS engine for Java. It
shipped with Java distributions starting with Java 8 and was eventually removed
in Java 15. The project was spun off and a compatible standalone release is
available for Java 15+.
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[SheetJS](https://sheetjs.com) is a JavaScript library for reading and writing
data from spreadsheets.
The ["Complete Example"](#complete-example) section includes a complete Java
command-line tool for reading data from spreadsheets and printing CSV rows.
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## Integration Details
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### Initialize Nashorn
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Nashorn does not provide a `global` variable. It must be created:
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```java
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Scanner;
/* initialize nashorn engine */
ScriptEngine engine = (new ScriptEngineManager()).getEngineByName("javascript");
/* create global */
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// highlight-next-line
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engine.eval("var global = (function(){ return this; }).call(null);");
```
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### Load SheetJS Scripts
The [SheetJS Standalone scripts](/docs/getting-started/installation/standalone)
can be parsed and evaluated in a Nashorn context.
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The main library can be loaded by reading the script from the file system and
evaluating in the Nashorn context:
```java
engine.eval(new Scanner(
SheetJS.class.getResourceAsStream("/xlsx.full.min.js")
).useDelimiter("\\Z").next());
```
To confirm the library is loaded, `XLSX.version` can be printed using the
Nashorn `print` built-in:
```java
engine.eval("print('SheetJS Version ' + XLSX.version);");
```
### Reading Files
Nashorn does not properly project `byte[]` into a JS array or `Int8Array`. The
recommended workaround is to copy the data in the JS context using the JS code:
```js
function b2a(b) {
var out = typeof Uint8Array == 'function' ? new Uint8Array(b.length) : new Array(b.length);
/* `b` is similar to Int8Array (values in the range -128 .. 127 ) */
for(var i = 0; i < out.length; i++) out[i] = (b[i] + 256) & 0xFF;
return out;
}
```
This function should be embedded in the Java code:
```java
/* read spreadsheet bytes */
engine.put("bytes", Files.readAllBytes(Paths.get(args[0])));
/* convert signed byte array to JS Uint8Array or unsigned byte array */
engine.eval(
"function b2a(b) {" +
"var out = typeof Uint8Array == 'function' ? new Uint8Array(b.length) : new Array(b.length);" +
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"for(var i = 0; i < out.length; i++) out[i] = b[i] & 0xFF;" +
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"return out;" +
"}" +
"var u8a = b2a(bytes)"
);
/* parse workbook */
engine.eval("var wb = XLSX.read(u8a, {type: 'array'})");
```
## Complete Example
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:::note Tested Deployments
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This demo was tested in the following deployments:
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| OpenJDK | Nashorn | Date |
|:--------|:----------------|:-----------|
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| 22 | 15.4 standalone | 2024-03-23 |
| 21.0.2 | 15.4 standalone | 2024-03-23 |
| 20.0.2 | 15.4 standalone | 2024-03-23 |
| 19.0.2 | 15.4 standalone | 2024-03-23 |
| 18.0.2 | 15.4 standalone | 2024-03-23 |
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| 17.0.10 | 15.4 standalone | 2024-03-25 |
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| 16.0.1 | 15.4 standalone | 2024-03-23 |
| 15.0.10 | 15.4 standalone | 2024-03-23 |
| 14.0.2 | Built-in | 2024-03-23 |
| 13.0.14 | Built-in | 2024-03-23 |
| 12.0.2 | Built-in | 2024-03-23 |
| 11.0.20 | Built-in | 2024-03-23 |
| 10.0.2 | Built-in | 2024-03-23 |
| 9 | Built-in | 2024-03-23 |
| 1.8.0 | Built-in | 2024-03-23 |
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:::
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### Compilation
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<Tabs groupId="java">
<TabItem value="stdlib" label="Java 8 - 14">
Nashorn is available without additional dependencies
</TabItem>
<TabItem value="standalone" label="Java 15+">
0) Download Nashorn and its dependencies:
```bash
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curl -L -o nashorn-core-15.4.jar "https://search.maven.org/remotecontent?filepath=org/openjdk/nashorn/nashorn-core/15.4/nashorn-core-15.4.jar"
curl -L -o asm-9.5.jar "https://search.maven.org/remotecontent?filepath=org/ow2/asm/asm/9.5/asm-9.5.jar"
curl -L -o asm-tree-9.5.jar "https://search.maven.org/remotecontent?filepath=org/ow2/asm/asm-tree/9.5/asm-tree-9.5.jar"
curl -L -o asm-commons-9.5.jar "https://search.maven.org/remotecontent?filepath=org/ow2/asm/asm-commons/9.5/asm-commons-9.5.jar"
curl -L -o asm-analysis-9.5.jar "https://search.maven.org/remotecontent?filepath=org/ow2/asm/asm-analysis/9.5/asm-analysis-9.5.jar"
curl -L -o asm-util-9.5.jar "https://search.maven.org/remotecontent?filepath=org/ow2/asm/asm-util/9.5/asm-util-9.5.jar"
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```
</TabItem>
</Tabs>
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1) Download the SheetJS Standalone script, shim script and test file. Move all
three files to the project directory:
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<ul>
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<li><a href={`https://cdn.sheetjs.com/xlsx-${current}/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-${current}/package/dist/shim.min.js`}>shim.min.js</a></li>
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<li><a href="https://sheetjs.com/pres.xlsx">pres.xlsx</a></li>
</ul>
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<CodeBlock language="bash">{`\
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curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/xlsx.full.min.js
curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/shim.min.js
curl -LO https://sheetjs.com/pres.xlsx`}
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</CodeBlock>
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2) Download [`SheetJSNashorn.java`](pathname:///nashorn/SheetJSNashorn.java):
```bash
curl -LO https://docs.sheetjs.com/nashorn/SheetJSNashorn.java
```
3) Build the sample class:
```bash
javac SheetJSNashorn.java
```
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This program tries to parse the file specified by the first argument and prints
CSV rows from the first worksheet.
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### Standalone Test
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4) Run the command directly:
<Tabs groupId="java">
<TabItem value="stdlib" label="Java 8 - 14">
```bash
java SheetJSNashorn pres.xlsx
```
</TabItem>
<TabItem value="standalone" label="Java 15+">
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Due to Java path inconsistencies, the command depends on the operating system:
<Tabs groupId="os">
<TabItem value="unix" label="Linux/MacOS">
```bash
java -cp ".:asm-9.5.jar:asm-tree-9.5.jar:asm-commons-9.5.jar:asm-analysis-9.5.jar:asm-util-9.5.jar:nashorn-core-15.4.jar" SheetJSNashorn pres.xlsx
```
</TabItem>
<TabItem value="win" label="Windows">
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```bash
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java -cp ".;asm-9.5.jar;asm-tree-9.5.jar;asm-commons-9.5.jar;asm-analysis-9.5.jar;asm-util-9.5.jar;nashorn-core-15.4.jar" SheetJSNashorn pres.xlsx
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```
</TabItem>
</Tabs>
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</TabItem>
</Tabs>
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If successful, CSV rows from the first worksheet will be displayed.
### Java Archive Test
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5) Assemble a Java Archive:
```bash
jar -cf SheetJSNashorn.jar SheetJSNashorn.class xlsx.full.min.js shim.min.js
```
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6) Create new directory and copy the archives and test file:
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```bash
mkdir -p sheethorn
cp *.jar pres.xlsx sheethorn
cd sheethorn
```
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7) Run the program using the Java Archive:
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<Tabs groupId="java">
<TabItem value="stdlib" label="Java 8 - 14">
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Due to Java path inconsistencies, the command depends on the operating system:
<Tabs groupId="os">
<TabItem value="unix" label="Linux/MacOS">
```bash
java -cp ".:SheetJSNashorn.jar" SheetJSNashorn pres.xlsx
```
</TabItem>
<TabItem value="win" label="Windows">
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```bash
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java -cp ".;SheetJSNashorn.jar" SheetJSNashorn pres.xlsx
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```
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</TabItem>
</Tabs>
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</TabItem>
<TabItem value="standalone" label="Java 15+">
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Due to Java path inconsistencies, the command depends on the operating system:
<Tabs groupId="os">
<TabItem value="unix" label="Linux/MacOS">
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```bash
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java -cp ".:asm-9.5.jar:asm-tree-9.5.jar:asm-commons-9.5.jar:asm-analysis-9.5.jar:asm-util-9.5.jar:nashorn-core-15.4.jar:SheetJSNashorn.jar" SheetJSNashorn pres.xlsx
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```
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</TabItem>
<TabItem value="win" label="Windows">
```bash
java -cp ".;asm-9.5.jar;asm-tree-9.5.jar;asm-commons-9.5.jar;asm-analysis-9.5.jar;asm-util-9.5.jar;nashorn-core-15.4.jar;SheetJSNashorn.jar" SheetJSNashorn pres.xlsx
```
</TabItem>
</Tabs>
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</TabItem>
</Tabs>
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This should print the same CSV rows from Step 4.