Gson具体用法

来源：http://xuexizhishen.blog.51cto.com/2687197/744910

package com.lupeng.javase.json.bean;import java.io.Serializable;/** * 普通JavaBean类 * @author 翔林小刚 * @date   2011-12-18 */public class JavaBean implements Serializable{ private static final long serialVersionUID = 8720431164344424704L; private String id; private String name; private int age; private String addr; public JavaBean() {  super(); } public JavaBean(String id, String name, int age, String addr) {  super();  this.id = id;  this.name = name;  this.age = age;  this.addr = addr; } public String getId() {  return id; } public void setId(String id) {  this.id = id; } public String getName() {  return name; } public void setName(String name) {  this.name = name; } public int getAge() {  return age; } public void setAge(int age) {  this.age = age; } public String getAddr() {  return addr; } public void setAddr(String addr) {  this.addr = addr; } @Override public String toString() {  return "User [id=" + id + ", name=" + name + ", age=" + age + ", addr=" + addr + "]"; }}-------------------------------------------------无情分割线--------------------------------------------package com.lupeng.javase.json.bean;import java.io.Serializable;import java.util.Date;/** * 带日期属性的JavaBean类 * @author 翔林小刚 * @date   2011-12-18 */public class DateBean implements Serializable { private static final long serialVersionUID = -2071405788146467301L; private String id; private String name; private int age; private Date birth; public DateBean() {  super(); } public DateBean(String id, String name, int age, Date birth) {  super();  this.id = id;  this.name = name;  this.age = age;  this.birth = birth; } public String getId() {  return id; } public void setId(String id) {  this.id = id; } public String getName() {  return name; } public void setName(String name) {  this.name = name; } public int getAge() {  return age; } public void setAge(int age) {  this.age = age; } public Date getBirth() {  return birth; } public void setBirth(Date birth) {  this.birth = birth; } @Override public String toString() {  return "DateBean [age=" + age + ", birth=" + birth + ", id=" + id    + ", name=" + name + "]"; }}-------------------------------------------------无情分割线--------------------------------------------package com.lupeng.javase.json.util;import java.lang.reflect.Type;import com.google.gson.JsonDeserializationContext;import com.google.gson.JsonDeserializer;import com.google.gson.JsonElement;import com.google.gson.JsonParseException;/** * 日期序列化实用工具类 * @author 翔林小刚 * @date   2011-12-18 */public class DateDeserializerUtils implements JsonDeserializer<java.util.Date>{ @Override public java.util.Date deserialize(JsonElement json, Type type,   JsonDeserializationContext context) throws JsonParseException {  return new java.util.Date(json.getAsJsonPrimitive().getAsLong()); }}-------------------------------------------------无情分割线--------------------------------------------package com.lupeng.javase.json.util;import java.lang.reflect.Type;import java.util.Date;import com.google.gson.JsonElement;import com.google.gson.JsonPrimitive;import com.google.gson.JsonSerializationContext;import com.google.gson.JsonSerializer;/** * 日期解序列实用工具类 * @author 翔林小刚 * @date   2011-12-18 */public class DateSerializerUtils implements JsonSerializer<java.util.Date>{ @Override public JsonElement serialize(Date date, Type type, JsonSerializationContext content) {  return new JsonPrimitive(date.getTime()); }}-------------------------------------------------无情分割线--------------------------------------------package com.lupeng.javase.apps.json;import java.text.DateFormat;import java.util.ArrayList;import java.util.Date;import java.util.HashMap;import java.util.List;import java.util.Map;import org.junit.Before;import org.junit.Test;import com.google.gson.Gson;import com.google.gson.GsonBuilder;import com.lupeng.javase.json.bean.DateBean;import com.lupeng.javase.json.bean.JavaBean;import com.lupeng.javase.json.util.DateDeserializerUtils;import com.lupeng.javase.json.util.DateSerializerUtils;/** * Google Gson解析Json数据实例 *  * 1.Bean、Json转换 testBeanJson() 2.List -> Json转换 testList2Json() * 3.泛型List、Json相互转换 testGenericList2Json() 4.Map -> Json转换 testMap2Json() * 5.泛型Map、Json相互转换 testGenericMap2Json() 6.带日期属性Bean、Json转换 testDateBeanJson() * 7.带日期属性泛型List、Json转换 testDateGenericListJson() *  * @author 翔林小刚 * @create 2011-08-05 * @modify 2011-12-18 */@SuppressWarnings("unchecked")public class GsonTester { private Gson gson = null; private GsonBuilder gsonBuilder = null; @Before public void setUp() {  gson = new Gson();  gsonBuilder = new GsonBuilder(); } /**  * JavaBean、Json相互转换  */ @Test public void testBeanJson() {  JavaBean bean = new JavaBean("1001", "scott", 20, "TL");  // Bean -> Json  String json = gson.toJson(bean);  System.out.println(json);  // Json -> Bean  bean = gson.fromJson(json, JavaBean.class);  System.out.println(bean); } /**  * List转换成Json字符串  */ @Test public void testList2Json() {  // List  List list = new ArrayList();  for (int i = 0; i < 5; i++) {   list.add("element" + i);  }  System.out.println(list);  // List -> Json  String json = gson.toJson(list);  System.out.println(json); } /**  * 泛型List、Json相互转换  */ @Test public void testGenericListJson() {  // 泛型List  List<JavaBean> list = new ArrayList<JavaBean>();  for (int i = 0; i < 3; i++) {   JavaBean user = new JavaBean("100" + i, "name" + i, 20 + i, "BJ"     + i);   list.add(user);  }  System.out.println(list);  // 泛型List -> Json  java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<List<JavaBean>>() {  }.getType();  String json = gson.toJson(list, type);  System.out.println(json);  // Json -> 泛型List  List<JavaBean> users = gson.fromJson(json.toString(), type);  System.out.println(users); } /**  * Map转换成Json字符串  */ @Test public void testMap2Json() {  // Map数据  Map map = new HashMap();  map.put("id", "1001");  map.put("name", "scott");  map.put("age", 20);  map.put("addr", "BJ");  System.out.println(map);  // Map -> Json  String json = gson.toJson(map);  System.out.println(json); } /**  * 泛型Map、Json相互转换  */ @Test public void testGenericMapJson() {  // 泛型Map数据  Map<String, JavaBean> map = new HashMap<String, JavaBean>();  for (int i = 0; i < 5; i++) {   JavaBean user = new JavaBean("100" + i, "name" + i, 20 + i, "LN"     + i);   map.put("100" + i, user);  }  System.out.println(map);  // 泛型Map -> Json  java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<Map<String, JavaBean>>() {  }.getType();  String json = gson.toJson(map, type);  System.out.println(json);  // Json -> Map  Map<String, JavaBean> users = gson.fromJson(json.toString(), type);  System.out.println(users); } /**  * 带日期类型Bean、Json相互转换  */ @Test public void testDateBeanJson() {  // 日期Bean数据  DateBean bean = new DateBean("1001", "scott", 20, new Date());  // Bean(带日期属性) -> Json  gson = gsonBuilder.registerTypeAdapter(java.util.Date.class,    new DateSerializerUtils()).setDateFormat(DateFormat.LONG)    .create();  // gson = new  // GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create();  String json = gson.toJson(bean);  System.out.println("_________________________" + json);  // Json -> Bean(带日期类型属性)  gson = gsonBuilder.registerTypeAdapter(java.util.Date.class,new DateDeserializerUtils()).setDateFormat("yyyy/MM/dd")    .create();  java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<DateBean>() {  }.getType();  DateBean b = gson.fromJson(json, type);  System.out.println(b); } /**  * 泛型日期List、Json相互转换  */ @Test public void testDateGenericListJson() {  // 泛型日期List  List<DateBean> list = new ArrayList<DateBean>();  for (int i = 0; i < 3; i++) {   DateBean user = new DateBean("100" + i, "name" + i, 20 + i,     new Date());   list.add(user);  }  System.out.println(list);  // 泛型日期List -> Json  gson = gsonBuilder.registerTypeAdapter(java.util.Date.class,    new DateSerializerUtils()).setDateFormat(DateFormat.LONG)    .create();  java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<List<DateBean>>() {  }.getType();  String json = gson.toJson(list, type);  System.out.println(json);  // Json -> 泛型日期List  gson = gsonBuilder.registerTypeAdapter(java.util.Date.class,    new DateDeserializerUtils()).setDateFormat(DateFormat.LONG)    .create();  List<DateBean> users = gson.fromJson(json.toString(), type);  System.out.println(users); }}