json tutorials

json-tutorials/json-jackson-example/pom.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0"?>
+<project
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>net.aimeizi</groupId>
+		<artifactId>json-tutorials</artifactId>
+		<version>1.0.0</version>
+	</parent>
+	<artifactId>json-jackson-example</artifactId>
+	<packaging>jar</packaging>
+	<name>json-jackson-example</name>
+	<url>http://maven.apache.org</url>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+	</properties>
+
+	<repositories>
+		<repository>
+			<id>codehaus</id>
+			<url>http://repository.codehaus.org/org/codehaus</url>
+		</repository>
+	</repositories>
+
+	<dependencies>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.6</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.codehaus.jackson</groupId>
+			<artifactId>jackson-mapper-asl</artifactId>
+			<version>1.9.9</version>
+		</dependency>
+	</dependencies>
+</project>

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/JacksonGeneratorExample.java

@@ -0,0 +1,49 @@
+package org.json.jackson.example;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.codehaus.jackson.JsonEncoding;
+import org.codehaus.jackson.JsonFactory;
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.JsonGenerator;
+import org.codehaus.jackson.map.JsonMappingException;
+
+public class JacksonGeneratorExample {
+
+	public static void main(String[] args) {
+
+		try {
+
+			JsonFactory jfactory = new JsonFactory();
+
+			/*** write to file ***/
+			JsonGenerator jGenerator = jfactory.createJsonGenerator(new File("src/main/resources/user.json"), JsonEncoding.UTF8);
+			jGenerator.writeStartObject(); // {
+
+			jGenerator.writeStringField("name", "mkyong"); // "name" : "mkyong"
+			jGenerator.writeNumberField("age", 29); // "age" : 29
+
+			jGenerator.writeFieldName("messages"); // "messages" :
+			jGenerator.writeStartArray(); // [
+
+			jGenerator.writeString("msg 1"); // "msg 1"
+			jGenerator.writeString("msg 2"); // "msg 2"
+			jGenerator.writeString("msg 3"); // "msg 3"
+
+			jGenerator.writeEndArray(); // ]
+
+			jGenerator.writeEndObject(); // }
+
+			jGenerator.close();
+
+		} catch (JsonGenerationException e) {
+			e.printStackTrace();
+		} catch (JsonMappingException e) {
+			e.printStackTrace();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/JacksonParserExample.java

@@ -0,0 +1,78 @@
+package org.json.jackson.example;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.codehaus.jackson.JsonFactory;
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.JsonParser;
+import org.codehaus.jackson.JsonToken;
+import org.codehaus.jackson.map.JsonMappingException;
+
+public class JacksonParserExample {
+
+	public static void main(String[] args) {
+
+		try {
+
+			JsonFactory jfactory = new JsonFactory();
+
+			/*** read from file ***/
+			JsonParser jParser = jfactory.createJsonParser(new File("src/main/resources/user.json"));
+
+			// loop until token equal to "}"
+			while (jParser.nextToken() != JsonToken.END_OBJECT) {
+
+				String fieldname = jParser.getCurrentName();
+				if ("name".equals(fieldname)) {
+
+					// current token is "name",
+					// move to next, which is "name"'s value
+					jParser.nextToken();
+					System.out.println(jParser.getText()); // display mkyong
+
+				}
+
+				if ("age".equals(fieldname)) {
+
+					// current token is "age",
+					// move to next, which is "name"'s value
+					jParser.nextToken();
+					System.out.println(jParser.getIntValue()); // display 29
+
+				}
+
+				if ("messages".equals(fieldname)) {
+
+					jParser.nextToken(); // current token is "[", move next
+
+					// messages is array, loop until token equal to "]"
+					while (jParser.nextToken() != JsonToken.END_ARRAY) {
+
+						// display msg1, msg2, msg3
+						System.out.println(jParser.getText());
+
+					}
+
+				}
+
+			}
+			jParser.close();
+
+		} catch (JsonGenerationException e) {
+
+			e.printStackTrace();
+
+		} catch (JsonMappingException e) {
+
+			e.printStackTrace();
+
+		} catch (IOException e) {
+
+			e.printStackTrace();
+
+		}
+
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/JacksonTreeNode.java

@@ -0,0 +1,64 @@
+package org.json.jackson.example;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.Iterator;
+
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.JsonNode;
+import org.codehaus.jackson.map.JsonMappingException;
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.node.ObjectNode;
+
+public class JacksonTreeNode {
+
+	public static void main(String[] args) {
+
+		ObjectMapper mapper = new ObjectMapper();
+
+		try {
+
+			BufferedReader fileReader = new BufferedReader(new FileReader("src/main/resources/user.json"));
+			JsonNode rootNode = mapper.readTree(fileReader);
+
+			/*** read ***/
+			JsonNode nameNode = rootNode.path("name");
+			System.out.println(nameNode.getTextValue());
+
+			JsonNode ageNode = rootNode.path("age");
+			System.out.println(ageNode.getIntValue());
+
+			JsonNode msgNode = rootNode.path("messages");
+			Iterator<JsonNode> ite = msgNode.getElements();
+
+			while (ite.hasNext()) {
+				JsonNode temp = ite.next();
+				System.out.println(temp.getTextValue());
+			}
+
+			/*** update ***/
+			((ObjectNode) rootNode).put("nickname", "new nickname");
+			((ObjectNode) rootNode).put("name", "updated name");
+			((ObjectNode) rootNode).remove("age");
+
+			mapper.writerWithDefaultPrettyPrinter().writeValue(new File("target/user.json"), rootNode);
+
+		} catch (JsonGenerationException e) {
+
+			e.printStackTrace();
+
+		} catch (JsonMappingException e) {
+
+			e.printStackTrace();
+
+		} catch (IOException e) {
+
+			e.printStackTrace();
+
+		}
+
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/Json2Object.java

@@ -0,0 +1,41 @@
+package org.json.jackson.example;
+
+import java.io.IOException;
+
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.map.JsonMappingException;
+import org.codehaus.jackson.map.ObjectMapper;
+
+public class Json2Object {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		
+		ObjectMapper mapper = new ObjectMapper();
+		 
+		try {
+	 
+			// read from file, convert it to user class
+			User user = mapper.readValue(ClassLoader.getSystemResourceAsStream("user.json"), User.class);
+	 
+			// display to console
+			System.out.println(user);
+	 
+		} catch (JsonGenerationException e) {
+	 
+			e.printStackTrace();
+	 
+		} catch (JsonMappingException e) {
+	 
+			e.printStackTrace();
+	 
+		} catch (IOException e) {
+	 
+			e.printStackTrace();
+	 
+		}
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/JsonFile2Map.java

@@ -0,0 +1,40 @@
+package org.json.jackson.example;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Map;
+
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.type.TypeReference;
+
+public class JsonFile2Map {
+
+	public static void main(String[] args) {
+
+		try {
+
+			ObjectMapper mapper = new ObjectMapper();
+
+			// read JSON from a file
+			Map<String, Object> map = mapper.readValue(
+					new File("src/main/resources/user.json"),
+					new TypeReference<Map<String, Object>>() {
+					});
+
+			System.out.println(map.get("name"));
+			System.out.println(map.get("age"));
+
+			@SuppressWarnings("unchecked")
+			ArrayList<String> list = (ArrayList<String>) map.get("messages");
+
+			for (String msg : list) {
+				System.out.println(msg);
+			}
+
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/JsonString2Map.java

@@ -0,0 +1,29 @@
+package org.json.jackson.example;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.type.TypeReference;
+
+public class JsonString2Map {
+
+	public static void main(String[] args) {
+		String json = "{\"name\":\"mkyong\", \"age\":\"29\"}";
+
+		Map<String, String> map = new HashMap<String, String>();
+		ObjectMapper mapper = new ObjectMapper();
+
+		try {
+
+			// convert JSON string to Map
+			map = mapper.readValue(json,new TypeReference<HashMap<String, String>>() {});
+
+			System.out.println(map);
+
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/Map2JsonFile.java

@@ -0,0 +1,36 @@
+package org.json.jackson.example;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.codehaus.jackson.map.ObjectMapper;
+
+public class Map2JsonFile {
+
+	public static void main(String[] args) {
+		ObjectMapper mapper = new ObjectMapper();
+		 
+		Map<String, Object> map = new HashMap<String, Object>();
+		map.put("name", "mkyong");
+		map.put("age", 29);
+	 
+		List<Object> list = new ArrayList<Object>();
+		list.add("msg 1");
+		list.add("msg 2");
+		list.add("msg 3");
+	 
+		map.put("messages", list);
+	 
+		try {
+	 
+			mapper.writerWithDefaultPrettyPrinter().writeValue(new File("src/main/resources/user.json"), map);
+	 
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/Map2JsonString.java

@@ -0,0 +1,31 @@
+package org.json.jackson.example;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.codehaus.jackson.map.ObjectMapper;
+
+public class Map2JsonString {
+
+	public static void main(String[] args) {
+		try {
+			 
+			ObjectMapper mapper = new ObjectMapper();
+			String json = "";
+	 
+			Map<String, String> map = new HashMap<String, String>();
+			map.put("name", "mkyong");
+			map.put("age", "29");
+	 
+			//convert map to JSON string
+			json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(map);
+	 
+			System.out.println(json);
+	 
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	 
+	}
+
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/Object2Json.java

@@ -0,0 +1,41 @@
+package org.json.jackson.example;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.map.JsonMappingException;
+import org.codehaus.jackson.map.ObjectMapper;
+
+public class Object2Json {
+
+	public static void main(String[] args) {
+		 
+		User user = new User();
+		ObjectMapper mapper = new ObjectMapper();
+	 
+		try {
+	 
+			// convert user object to json string, and save to a file
+			mapper.writerWithDefaultPrettyPrinter().writeValue(new File("src/main/resources/user.json"), user);
+	 
+			// display to console
+			System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(user));
+	 
+		} catch (JsonGenerationException e) {
+	 
+			e.printStackTrace();
+	 
+		} catch (JsonMappingException e) {
+	 
+			e.printStackTrace();
+	 
+		} catch (IOException e) {
+	 
+			e.printStackTrace();
+	 
+		}
+	 
+	  }
+	
+}

json-tutorials/json-jackson-example/src/main/java/org/json/jackson/example/User.java

@@ -0,0 +1,51 @@
+package org.json.jackson.example;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+
+@SuppressWarnings("serial")
+public class User implements Serializable{
+	
+	private int age = 29;
+	private String name = "mkyong";
+	
+	public int getAge() {
+		return age;
+	}
+
+	public void setAge(int age) {
+		this.age = age;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public List<String> getMessages() {
+		return messages;
+	}
+
+	public void setMessages(List<String> messages) {
+		this.messages = messages;
+	}
+
+	private List<String> messages = new ArrayList<String>() {
+		{
+			add("msg 1");
+			add("msg 2");
+			add("msg 3");
+		}
+	};
+ 
+	@Override
+	public String toString() {
+		return "User [age=" + age + ", name=" + name + ", " +
+				"messages=" + messages + "]";
+	}
+	
+}

json-tutorials/json-jackson-example/src/main/resources/user.json

@@ -0,0 +1 @@
+{"name":"mkyong","age":29,"messages":["msg 1","msg 2","msg 3"]}