Java操作JSON数据(2)--Gson操作JSON数据，
Gson是Google公司发布的一个开发源码的Java库，可用于将Java对象转换为JSON字符串，也可用于将JSON字符串转换为对应的Java对象。本介绍下Gson的基本使用方法，包括序列化和反序列化；文中所使用到的软件版本：Java 1.8.0_191、Gson 2.8.6。
1、引入依赖
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.6</version>
</dependency>
2、序列化
public static String serialize() {
MyBean bean = new MyBean();
bean.setS("测试字符串");
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.HOUR_OF_DAY, -1);
bean.setD(calendar.getTime());
List<MyBean> list = new ArrayList<MyBean>();
list.add(bean);
Map<String, List<MyBean>> map = new HashMap<String, List<MyBean>>();
map.put("data", list);
Gson gson = new GsonBuilder()
.serializeNulls() //序列化值为null的字段
.setDateFormat("yyyy-MM-dd HH:mm:ss") //设置日期格式
.excludeFieldsWithModifiers(Modifier.STATIC)//根据修饰符过滤字段
.create();
String result = gson.toJson(map);
System.out.println(result);
return result;
}
3、反序列化
public static void deserialize() {
String s = serialize();
Gson gson = new GsonBuilder()
.setDateFormat("yyyy-MM-dd HH:mm:ss") //设置日期格式
.create();
Type type = new TypeToken<Map<String, List<MyBean>>>(){}.getType();
Map<String, List<MyBean>> map = gson.fromJson(s, type);
System.out.println(map);
//直接通过api获取相应数据
JsonElement element = JsonParser.parseString(s);
JsonArray data = element.getAsJsonObject().getAsJsonArray("data");
JsonObject bean = data.get(0).getAsJsonObject();
System.out.println(bean.get("s").getAsString());
//...
}
4、完整例子
![]()
package com.inspur.demo.json;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.reflect.TypeToken;
/**
* Gson操作JSON数据
*/
public class GsonCase {
/**
* 序列化
*/
public static String serialize() {
MyBean bean =
new MyBean();
bean.setS("测试字符串"
);
Calendar calendar =
Calendar.getInstance();
calendar.add(Calendar.HOUR_OF_DAY, -1
);
bean.setD(calendar.getTime());
List<MyBean> list =
new ArrayList<MyBean>
();
list.add(bean);
Map<String, List<MyBean>> map =
new HashMap<String, List<MyBean>>
();
map.put("data"
, list);
Gson gson =
new GsonBuilder()
.serializeNulls() //序列化值为null的字段
.setDateFormat("yyyy-MM-dd HH:mm:ss")
//设置日期格式
.excludeFieldsWithModifiers(Modifier.STATIC)
//根据修饰符过滤字段
.create();
String result =
gson.toJson(map);
System.out.println(result);
return result;
}
/**
* 反序列化
*/
public static void deserialize() {
String s =
serialize();
Gson gson =
new GsonBuilder()
.setDateFormat("yyyy-MM-dd HH:mm:ss")
//设置日期格式
.create();
Type type =
new TypeToken<Map<String, List<MyBean>>>
(){}.getType();
Map<String, List<MyBean>> map =
gson.fromJson(s, type);
System.out.println(map);
//直接通过api获取相应数据
JsonElement element =
JsonParser.parseString(s);
JsonArray data = element.getAsJsonObject().getAsJsonArray("data"
);
JsonObject bean = data.get(0
).getAsJsonObject();
System.out.println(bean.get("s"
).getAsString());
//...
}
public static void main(String[] args) {
serialize();
deserialize();
}
}
GsonCase
![]()
package com.inspur.demo.json;
import java.util.Arrays;
import java.util.Date;
public class MyBean {
private String s = "字符串"
;
private String s2;
private String s3 = "字符串3"
;
private int i = 123
;
private Integer i2;
private char c = '到'
;
private char[] c2 =
new char[]{'a', 'b'
};
private Date d =
new Date();
private Date[] d2 =
new Date[]{
new Date(),
new Date()};
public String getS() {
return s;
}
public void setS(String s) {
this.s =
s;
}
public String getS2() {
return s2;
}
public void setS2(String s2) {
this.s2 =
s2;
}
public String getS3() {
return s3;
}
public void setS3(String s3) {
this.s3 =
s3;
}
public int getI() {
return i;
}
public void setI(
int i) {
this.i =
i;
}
public Integer getI2() {
return i2;
}
public void setI2(Integer i2) {
this.i2 =
i2;
}
public char getC() {
return c;
}
public void setC(
char c) {
this.c =
c;
}
public char[] getC2() {
return c2;
}
public void setC2(
char[] c2) {
this.c2 =
c2;
}
public Date getD() {
return d;
}
public void setD(Date d) {
this.d =
d;
}
public Date[] getD2() {
return d2;
}
public void setD2(Date[] d2) {
this.d2 =
d2;
}
@Override
public String toString() {
return "MyBean [s=" + s + ", s2=" + s2 + ", s3=" + s3 + ", i=" + i + ", i2=" + i2 + ", c=" + c + ", c2="
+ Arrays.toString(c2) + ", d=" + d + ", d2=" + Arrays.toString(d2) + "]"
;
}
}
MyBean
用户点评