Json

Convenience library for handling JSON objects in Java. Goals:

• Usability
• Minimise verbosity
• Play well with Nashorn JavaScript engine from Java 8

In essence Json is just a thin wrapper around a Map where properties are stored. There are lots of functions to manipulate a Map such as in Guava or Apache Commons, and you should be able to re-use them. Additional Map utilities are provided here.

    Json addr = new Json() {
    	String host = "localhost";
    	int port = 80;
    };
    	 
    addr.toString(); 	// {"host": "localhost", "port": 80}
    addr.set("path", "/").set("proto", "http");
    addr.get("port"); 	// 80

See tests for more examples.

Features

• Simple and convenient constructors
• Implements Map interface so you can treat it like a Map of Maps
• JDK8 Nashorn compatible - use it in JavaScript functions
• Convenience methods for building and getting values
• Serialize to/from String
• Access properties without explicit casting
• Provides equals/hashCode, so you can store Json in collections

Download

Grab it from JitPack

Json depends on Jackson

Constructors

    new Json("{port: 80}"); // from string. quotes around field names are optional.
    new Json( hashMap );  // from map
    new Json("port", 80); // key-value
    new Json() { int port = 80; } // from fields 
    new Json("{port: 80} // listen port"); // comments are allowed

Factory methods

    Json json = Json.of.url("https://status.github.com/api/status.json"); // download from url
    Json json = Json.of.bytes(byteArray);
    Json json = Json.of.file("/path/to/file.json");
    Json json = Json.of.bean(beanObject);
    Json json = Json.of.string("{port: 80}");
    Json json = Json.of.keyVal("port" 80, "host", "localhost"); // key-value pairs
    Json json = Json.of.stream(inputStream);

Operations

    Json json = new Json().set("port", 80)
                          .set("host", "localhost"); // chain calls
    
    int port = json.get("port", 0); // get or return default. avoid casting 
     
    Json nested = json.at("path", "to", "nested"); // json.path.to.nested
    
    json.merge( anotherJson ); // merge values recursively
    
    json.copy(); // deep copy

As well as all the methods from Map:

• isEmpty(), keySet(), containsKey(), entrySet(), ...

Scripting usage

You can pass Json to Nashorn JavaScript functions and treat it like a native JSON object:

    Json addr = new Json("port", 80);

    scriptEngine.eval("function nextPort(addr) { addr.port++; }");

    invocable.invokeFunction("nextPort", addr);
		
    out.println( addr.get("port") ); // 81

Build

`./gradlew jar`

Note: running tests requires JDK 8 due to Nashorn tests.

License

Apache 2.0