一、Android原生技术解析Json数据
1.1 将json格式的字符串{}转换为Java对象
1.1.1 API
JSONObject(String json) : 将json字符串解析为json对象
Xxx getXxx(String name) : 根据name, 在json对象中得到对应的Value
Xxx optXxx(String name) : 根据name, 在json对象中得到对应的Value
注意：optXxx方法会在对应的key中的值不存在的时候返回一个空字符串或者返回你指定的默认值，但是getString()方法当key中的值不存在时会出现空指针异常的错误。
1.1.2 测试数据
{
"id":2,
"name":"大虾",
"price":12.3,
"imagePath":"http://192.168.10.165:8080/L05_Server/images/f1.jpg"
}
1.1.3 代码实现
//解析数据
try {
JSONObject jsonObject = new JSONObject(json);
int id = jsonObject.optInt("id");
String name = jsonObject.optString("name");
double price = jsonObject.optDouble("price");
String imagePath = jsonObject.optString("imagePath");
shopInfo = new ShopInfo(id, name, price, imagePath);
} catch (JSONException e) {
e.printStackTrace();
}
1.2 将json格式的字符串[]转换为Java对象的List
1.2.1 API
JSONArray(String json) : 将json字符串解析为json数组
int length() : 得到json数组中元素的个数
Xxx getXxx(int index) : 根据下标得到json数组中对应的元素数据
Xxx optXxx(int index) : 根据下标得到json数组中对应的元素数据
注意：optXxx方法会在对应的key中的值不存在的时候返回一个空字符串或者返回你指定的默认值，但是getString()方法当key中的值不存在时会出现空指针异常的错误。
1.2.2 测试数据
[
{
"id": 1,
"imagePath": "http://192.168.10.165:8080/f1.jpg",
"name": "大虾1",
"price": 12.3
},
{
"id": 2,
"imagePath": "http://192.168.10.165:8080/f2.jpg",
"name": "大虾2",
"price": 12.5
}
]
1.2.3 代码实现
//解析Json数据
ArrayList<ShopInfo> shopInfos = new ArrayList<>();
try {
JSONArray jsonArray = new JSONArray(json);
for (int i = 0;i<jsonArray.length();i++){
JSONObject jsonObject = jsonArray.getJSONObject(i);
int id = jsonObject.optInt("id");
String name = jsonObject.optString("name");
double price = jsonObject.optDouble("price");
String imagePath = jsonObject.optString("imagePath");
ShopInfo shopInfo = new ShopInfo(id, name, price, imagePath);
shopInfos.add(shopInfo);
}
} catch (JSONException e) {
e.printStackTrace();
}
1.3 复杂json数据解析
1.3.1 测试数据
{
"data": {
"count": 5,
"items": [
{
"id": 45,
"title": "坚果"
},
{
"id": 132,
"title": "炒货"
},
{
"id": 166,
"title": "蜜饯"
},
{
"id": 195,
"title": "果脯"
},
{
"id": 196,
"title": "礼盒"
}
]
},
"rs_code": "1000",
"rs_msg": "success"
}
1.3.2 使用HiJson工具格式化json数据
[HiJson](链接：https://pan.baidu.com/s/1QqKypwfvnn9eebSHLSXdQQ
提取码：hfm2 )
HiJson.png
1.3.3 使用GsonFormat插件在AndroidStudio中生成对应的bean
1.3.4 代码实现
先逐层解析，然后逐层封装
//解析数据,
try {
//第一层解析
JSONObject jsonObject = new JSONObject(json);
JSONObject data = jsonObject.optJSONObject("data");
String rs_code = jsonObject.optString("rs_code");
String rs_msg = jsonObject.optString("rs_msg");
//第一层封装
dateInfo = new DateInfo();
DateInfo.DataBean dataBean = new DateInfo.DataBean();
dateInfo.setData(dataBean);
dateInfo.setRs_code(rs_code);
dateInfo.setRs_msg(rs_msg);
//第二层解析
int count = data.optInt("count");
JSONArray items = data.optJSONArray("items");
//第二层封装
dataBean.setCount(count);
List<DateInfo.DataBean.ItemsBean> itemBean = new ArrayList<>();
dataBean.setItems(itemBean);
//第三层解析
for (int i = 0; i <items.length() ; i++) {
JSONObject jsonObject1 = items.optJSONObject(i);
if (jsonObject1 != null){
int id = jsonObject1.optInt("id");
String title = jsonObject1.optString("title");
//第三层封装
DateInfo.DataBean.ItemsBean itemsBean = new DateInfo.DataBean.ItemsBean();
itemsBean.setId(id);
itemsBean.setTitle(title);
itemBean.add(itemsBean);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
1.4 特殊json数据解析
1.4.1 测试数据
特殊在键名是0和1，不能通过GsonFormat自动生成bean类，只能手动写
{
"code": 0,
"list": {
"0": {
"aid": "6008965",
"author": "哔哩哔哩番剧",
"coins": 170,
"copyright": "Copy",
"create": "2016-08-25 21:34"
},
"1": {
"aid": "6008938",
"author": "哔哩哔哩番剧",
"coins": 404,
"copyright": "Copy",
"create": "2016-08-25 21:33"
}
}
}
1.4.2 手动写bean类
public class FileBean {
private int code;
private List<FilmBean> filmBeans;
@Override
public String toString() {
return "FileBean{" +
"code=" + code +
", filmBeans=" + filmBeans +
'}';
}
public int getCode() {
return code;
}
public void setCode(int code) {
this.code = code;
}
public List<FilmBean> getFilmBeans() {
return filmBeans;
}
public void setFilmBeans(List<FilmBean> filmBeans) {
this.filmBeans = filmBeans;
}
public static class FilmBean {
private String aid;
private String author;
private int coins;
private String copyright;
private String create;
@Override
public String toString() {
return "FileBean{" +
"aid='" + aid + '\'' +
", author='" + author + '\'' +
", coins=" + coins +
", copyright='" + copyright + '\'' +
", create='" + create + '\'' +
'}';
}
public String getAid() {
return aid;
}
public void setAid(String aid) {
this.aid = aid;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public int getCoins() {
return coins;
}
public void setCoins(int coins) {
this.coins = coins;
}
public String getCopyright() {
return copyright;
}
public void setCopyright(String copyright) {
this.copyright = copyright;
}
public String getCreate() {
return create;
}
public void setCreate(String create) {
this.create = create;
}
}
}
1.4.3 手动解析Json数据
//解析数据
try {
//第一层解析
JSONObject jsonObject = new JSONObject(json);
int code = jsonObject.optInt("code");
JSONObject list = jsonObject.optJSONObject("list");
//第一层封装
fileBean = new FileBean();
fileBean.setCode(code);
ArrayList<FileBean.FilmBean> fileBeans = new ArrayList<>();
fileBean.setFilmBeans(fileBeans);
//第二层解析
for (int i = 0; i < list.length(); i++) {
JSONObject jsonObject1 = list.optJSONObject(i + "");
String aid = jsonObject1.optString("aid");
String author = jsonObject1.optString("author");
int coins = jsonObject1.optInt("coins");
String copyright = jsonObject1.optString("copyright");
String create = jsonObject1.optString("create");
//第二层封装
FileBean.FilmBean filmBean = new FileBean.FilmBean();
filmBean.setAid(aid);
filmBean.setAuthor(author);
filmBean.setCoins(coins);
filmBean.setCopyright(copyright);
filmBean.setCreate(create);
fileBeans.add(filmBean);
}
} catch (JSONException e) {
e.printStackTrace();
}
二、Gson框架技术
下载Gson框架，下载地址
[Jar包](链接：https://pan.baidu.com/s/1hq00k7ZXm2Rypfof5_dhYA
提取码：yisw )
将Gson的jar包导入到项目中即可使用Gson
2.1 将json格式的字符串{}转换为Java对象
2.1.1 API
fromJson(String json, Class<T> classOfT);
第一个参数为json数据，第二个参数为对应的bean类。
注意：要求json对象中的key的名称与java对象对应的类中的属性名要相同。
2.1.2 测试数据
{
"id":2, "name":"大虾",
"price":12.3,
"imagePath":"http://192.168.10.165:8080/L05_Server/images/f1.jpg"
}
2.1.3 代码实现
//解析数据
Gson gson = new Gson();
ShopInfo shopInfo = gson.fromJson(json, ShopInfo.class);
2.2 将json格式的字符串[]转换为Java对象的List
2.2.1 API
List<ShopInfo> shops = gson.fromJson(json, new TypeToken<List<ShopInfo>>() {}.getType());
2.2.2 测试数据
[
{
"id": 1,
"imagePath": "http://192.168.10.165:8080/f1.jpg",
"name": "大虾1",
"price": 12.3
},
{
"id": 2,
"imagePath": "http://192.168.10.165:8080/f2.jpg",
"name": "大虾2",
"price": 12.5
}
]
2.2.3 代码实现
Gson gson = new Gson();
List<ShopInfo> shopInfos= gson.fromJson(json,
new TypeToken<List<ShopInfo>>() { }.getType());
2.3 将Java对象转换为json字符串{}
2.3.1 API
String toJson(Object src);
2.3.2 代码示例
/**
* 将Java对象转换为json字符串
*/
private void JavaToJsonObjectByGson() {
ShopInfo shopInfo = new ShopInfo(3, "螃蟹", 250.0, "pangxie");
Gson gson = new Gson();
String json = gson.toJson(shopInfo);
tvOriginal.setText(shopInfo.toString());
tvLast.setText(json);
}
2.4 将Java对象的List转换为json字符串[]
2.4.1 API
String toJson(Object src);
2.4.2 代码示例
/**
* Java对象的List转换为json
*/
private void JavaListToJsonByGson() {
ArrayList<ShopInfo> shops = new ArrayList<>();
ShopInfo haidai = new ShopInfo(4, "海带", 13.3, "haidai");
ShopInfo haima = new ShopInfo(5, "海马", 14.3, "haima");
shops.add(haidai);
shops.add(haima);
String json = new Gson().toJson(shops);
tvOriginal.setText(shops.toString());
tvLast.setText(json);
}
三、FastJson框架技术
下载FastJson，下载地址
[jar包](链接：https://pan.baidu.com/s/16g28Dd0TuOZWgDauRh7hWg
提取码：2pu1 )
3.1 将json格式的字符串{}转换为Java对象
3.1.1 API
注意：对应的bean类必须有默认的构造方法
parseObject(String json, Class<T> classOfT);
3.1.2 测试数据
{
"id":2, "name":"大虾",
"price":12.3,
"imagePath":"http://192.168.10.165:8080/L05_Server/images/f1.jpg"
}
3.1.3 代码示例
/**
* 将json转换为java对象
*/
private void JsonToJavaObjectByFastJson() {
String json = "{\n" +
"\t\"id\":2, \"name\":\"大虾\", \n" +
"\t\"price\":12.3, \n" +
"\t\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f1.jpg\"\n" +
"}\n";
ShopInfo shopInfo = JSON.parseObject(json, ShopInfo.class);
tvOriginal.setText(json);
tvLast.setText(shopInfo.toString());
}
3.2 将json格式的字符串[]转换为Java对象的List
3.2.1 API
List<T> parseArray(String json,Class<T> classOfT);
3.2.2 测试数据
[
{
"id": 1,
"imagePath": "http://192.168.10.165:8080/f1.jpg",
"name": "大虾1",
"price": 12.3
},
{
"id": 2,
"imagePath": "http://192.168.10.165:8080/f2.jpg",
"name": "大虾2",
"price": 12.5
}
]
3.2.3 代码示例
List<ShopInfo> shopInfos = JSON.parseArray(json, ShopInfo.class);
3.3 将Java对象转换为Json字符串
3.3.1 API
String toJSONString(Object object);
3.3.2 代码示例
/**
* java对象转换为json字符串
*/
private void JavaObjectToJson() {
ShopInfo shopInfo = new ShopInfo(7, "鱼", 1.3, "yu");
String json = JSON.toJSONString(shopInfo);
tvOriginal.setText(shopInfo.toString());
tvLast.setText(json);
}
3.4 将Java数组转换为Json字符串
3.4.1 API
String toJSONString(ArrayList<> lists);
3.4.2 代码演示
/**
* java数组转换为json字符串
*/
private void JavaListToJson() {
ShopInfo pingguo = new ShopInfo(6, "苹果", 5.0, "pingguo");
ShopInfo xeuli = new ShopInfo(7, "雪梨", 2.5, "xeuli");
ArrayList<ShopInfo> shops = new ArrayList<>();
shops.add(pingguo);
shops.add(xeuli);
String json = JSON.toJSONString(shops);
tvOriginal.setText(shops.toString());
tvLast.setText(json);
}
