package com.kaishengit.util.jackson;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.node.JsonNodeFactory;
public class JacksonTest {
private static JsonGenerator jsonGenerator = null;
private static ObjectMapper objectMapper = null;
private static AccountBean bean = null;
static {
bean = new AccountBean();
bean.setAddress("china-Guangzhou");
bean.setEmail("hoojo_@126.com");
bean.setId(1);
bean.setName("hoojo");
objectMapper = new ObjectMapper();
try {
jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(
System.out, JsonEncoding.UTF8);
} catch (IOException e) {
e.printStackTrace();
}
}
// public void init() {}
/*
* public void destory() { try { if (jsonGenerator != null) {
* jsonGenerator.flush(); } if (!jsonGenerator.isClosed()) {
* jsonGenerator.close(); } jsonGenerator = null; objectMapper = null; bean
* = null; System.gc(); } catch (IOException e) { e.printStackTrace(); } }
*/
// JavaBean(Entity/Model)转换成JSON
public static void writeEntityJSON() {
try {
System.out.println("jsonGenerator"); // writeObject可以转换java对象，eg:JavaBean/Map/List/Array等
jsonGenerator.writeObject(bean);
System.out.println();
System.out.println("ObjectMapper"); // writeValue具有和writeObject相同的功能
StringWriter strWriter = new StringWriter();
objectMapper.writeValue(strWriter, bean);
String s = strWriter.toString();
System.out.println("-----------------------");
System.out.println(s);
} catch (IOException e) {
e.printStackTrace();
}
}
// 将Map集合转换成Json字符串
public static void writeMapJSON() {
try {
Map<String, Object> map = new HashMap<String, Object>();
map.put("name", bean.getName());
map.put("account", bean);
bean = new AccountBean();
bean.setAddress("china-Beijin");
bean.setEmail("hoojo@qq.com");
map.put("account2", bean);
System.out.println("jsonGenerator");
jsonGenerator.writeObject(map);
System.out.println("");
System.out.println("objectMapper");
Writer strWriter = new StringWriter();
objectMapper.writeValue(strWriter, map);
System.out.println(strWriter.toString());
} catch (IOException e) {
e.printStackTrace();
}
}
// 将List集合转换成json
public static void writeListJSON() {
try {
List<AccountBean> list = new ArrayList<AccountBean>();
list.add(bean);
bean = new AccountBean();
bean.setId(2);
bean.setAddress("address2");
bean.setEmail("email2");
bean.setName("haha2");
list.add(bean);
System.out.println("jsonGenerator"); // list转换成JSON字符串
jsonGenerator.writeObject(list);
System.out.println();
System.out.println("ObjectMapper"); // 用objectMapper直接返回list转换成的JSON字符串
System.out.println("1###" + objectMapper.writeValueAsString(list));
System.out.print("2###"); // objectMapper list转换成JSON字符串
Writer strWriter = new StringWriter();
objectMapper.writeValue(strWriter, list);
System.out.println(strWriter.toString());
} catch (IOException e) {
e.printStackTrace();
}
}
public static void writeOthersJSON() {
try {
String[] arr = { "a", "b", "c" };
System.out.println("jsonGenerator");
String str = "hello world jackson!"; // byte
jsonGenerator.writeBinary(str.getBytes()); // boolean
jsonGenerator.writeBoolean(true); // null
jsonGenerator.writeNull(); // float
jsonGenerator.writeNumber(2.2f); // char
jsonGenerator.writeRaw("c"); // String
jsonGenerator.writeRaw(str, 5, 10); // String
jsonGenerator.writeRawValue(str, 5, 5); // String
jsonGenerator.writeString(str);
jsonGenerator.writeTree(JsonNodeFactory.instance.POJONode(str));
System.out.println(); // Object
jsonGenerator.writeStartObject();// {
jsonGenerator.writeObjectFieldStart("user");// user:{
jsonGenerator.writeStringField("name", "jackson");// name:jackson
jsonGenerator.writeBooleanField("sex", true);// sex:true
jsonGenerator.writeNumberField("age", 22);// age:22
jsonGenerator.writeEndObject();// }
jsonGenerator.writeArrayFieldStart("infos");// infos:[
jsonGenerator.writeNumber(22);// 22
jsonGenerator.writeString("this is array");// this is array
jsonGenerator.writeEndArray();// ]
jsonGenerator.writeEndObject();// }
AccountBean bean = new AccountBean();
bean.setAddress("address");
bean.setEmail("email");
bean.setId(1);
bean.setName("haha");
// complex Object
jsonGenerator.writeStartObject();// {
jsonGenerator.writeObjectField("user", bean);// user:{bean}
jsonGenerator.writeObjectField("infos", arr);// infos:[array]
jsonGenerator.writeEndObject();// }
} catch (Exception e) {
e.printStackTrace();
}
}
// 将json字符串转换成JavaBean对象
public static void readJson2Entity() {
String json = "{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}";
try {
AccountBean acc = objectMapper.readValue(json, AccountBean.class);
System.out.println(acc.getName());
System.out.println(acc);
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// 将json字符串转换成List<Map>集合
public static void readJson2List() {
String json = "[{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},"
+ "{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}]";
try {
List<LinkedHashMap<String, Object>> list = objectMapper.readValue(
json, List.class);
System.out.println(list.size());
for (int i = 0; i < list.size(); i++) {
Map<String, Object> map = list.get(i);
Set<String> set = map.keySet();
for (Iterator<String> it = set.iterator(); it.hasNext();) {
String key = it.next();
System.out.println(key + ":" + map.get(key));
}
}
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// Json字符串转换成Array数组
public static void readJson2Array() {
String json = "[{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},"
+ "{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}]";
try {
AccountBean[] arr = objectMapper.readValue(json,
AccountBean[].class);
System.out.println(arr.length);
for (int i = 0; i < arr.length; i++) {
System.out.println(arr[i]);
}
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// Json字符串转换成Map集合
public static void readJson2Map() {
String json = "{\"success\":true,\"A\":{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},"
+ "\"B\":{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}}";
try {
Map<String, Map<String, Object>> maps = objectMapper.readValue(
json, Map.class);
System.out.println(maps.size());
Set<String> key = maps.keySet();
Iterator<String> iter = key.iterator();
while (iter.hasNext()) {
String field = iter.next();
System.out.println(field + ":" + maps.get(field));
}
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
/*
* public void writeObject2Xml() { //stax2-api-3.0.2.jar
* System.out.println("XmlMapper"); XmlMapper xml = new XmlMapper(); try {
* //javaBean转换成xml //xml.writeValue(System.out, bean); StringWriter sw =
* new StringWriter(); xml.writeValue(sw, bean);
* System.out.println(sw.toString()); //List转换成xml List<AccountBean> list =
* new ArrayList<AccountBean>(); list.add(bean); list.add(bean);
* System.out.println(xml.writeValueAsString(list)); //Map转换xml文档
* Map<String, AccountBean> map = new HashMap<String, AccountBean>();
* map.put("A", bean); map.put("B", bean);
* System.out.println(xml.writeValueAsString(map)); } catch
* (JsonGenerationException e) { e.printStackTrace(); } catch
* (JsonMappingException e) { e.printStackTrace(); } catch (IOException e) {
* e.printStackTrace(); }}
*/
public static void main(String[] args) {
JacksonTest.writeEntityJSON();
// JacksonTest.writeMapJSON();
// JacksonTest.writeListJSON();
// JacksonTest.writeOthersJSON();
// JacksonTest.readJson2Entity();
// JacksonTest.readJson2List();
// JacksonTest.readJson2Array();
//JacksonTest.readJson2Map();
}
}