Question

使用gson解析怎么将json字符串解析为数组

Answer 1

步骤1:目标:将从webservice传回的json

1
{
"status": 0,
"result": {
"location": {
"lng": 103.98964143811,
"lat": 30.586643130352
},
"formatted_address": "四川省成都市双流县北一街154",
"business": "簇桥,金花桥",
"addressComponent": {
"city": "成都市",
"district": "双流县",
"province": "四川省",
"street": "北一街",
"street_number": "154"
},
"cityCode": 75
}
}
2
先普及下json数据格式定义: json数据只有两种格式.
一种是对象: 一个大括号包裹的内容就是一个对象.里面是无数个逗号相间隔的键值对
{ "firstName": "Brett", "lastName":"McLaughlin", "email": "aaaa" }
一种是数组:一个方括号包裹的内容就是一个数组,里面是无数个逗号相间隔的json对象
如:
{
"people": [
{
"firstName": "Brett",
"lastName": "McLaughlin",
"email": "aaaa"
},
{
"firstName": "Jason",
"lastName": "Hunter",
"email": "bbbb"
},
{
"firstName": "Elliotte",
"lastName": "Harold",
"email": "cccc"
}
]
}
END
步骤2 定义json数据格式对应的javaBean

1
public class Result {
private Integer status;
private ResultDetail result;

public Result() {
}

public Result(Integer status, ResultDetail result) {
super();
this.status = status;
this.result = result;
}

public ResultDetail getResult() {
return this.result;
}

public Integer getStatus() {
return this.status;
}

public void setResult( ResultDetail result ) {
this.result = result;
}

public void setStatus( Integer status ) {
this.status = status;
}

@Override
public String toString() {
return "Result [status=" + this.status + ", result=" + this.result
+ "]";
}

}
2
public class ResultDetail {
Location location;
String formatted_address;
AddressComponent addressComponent;
String business;
String cityCode;

public ResultDetail() {
super();
// TODO Auto-generated constructor stub
}

public ResultDetail(Location location, String formatted_address,
AddressComponent addressComponent, String business, String cityCode) {
super();
this.location = location;
this.formatted_address = formatted_address;
this.addressComponent = addressComponent;
this.business = business;
this.cityCode = cityCode;
}

public AddressComponent getAddressComponent() {
return this.addressComponent;
}

public String getBusiness() {
return this.business;
}

public String getCityCode() {
return this.cityCode;
}

public String getFormatted_address() {
return this.formatted_address;
}

public Location getLocation() {
return this.location;
}

public void setAddressComponent( AddressComponent addressComponent ) {
this.addressComponent = addressComponent;
}

public void setBusiness( String business ) {
this.business = business;
}

public void setCityCode( String cityCode ) {
this.cityCode = cityCode;
}

public void setFormatted_address( String formatted_address ) {
this.formatted_address = formatted_address;
}

public void setLocation( Location location ) {
this.location = location;
}

}
3
public class Location {
String lng;
String lat;

public Location() {

}

public Location(String lng, String lat) {
this.lng = lng;
this.lat = lat;
}

public String getLat() {
return this.lat;
}

public String getLng() {
return this.lng;
}

public void setLat( String lat ) {
this.lat = lat;
}

public void setLng( String lng ) {
this.lng = lng;
}

@Override
public String toString() {
return "Location [lng=" + this.lng + ", lat=" + this.lat + "]";
}

}
4
public class AddressComponent {
String city;
String district;
String province;
String street;
String street_number;

public AddressComponent() {
super();
// TODO Auto-generated constructor stub
}

public AddressComponent(String city, String district, String province,
String street, String street_number) {
super();
this.city = city;
this.district = district;
this.province = province;
this.street = street;
this.street_number = street_number;
}

public String getCity() {
return this.city;
}

public String getDistrict() {
return this.district;
}

public String getProvince() {
return this.province;
}

public String getStreet() {
return this.street;
}

public String getStreet_number() {
return this.street_number;
}

public void setCity( String city ) {
this.city = city;
}

public void setDistrict( String district ) {
this.district = district;
}

public void setProvince( String province ) {
this.province = province;
}

public void setStreet( String street ) {
this.street = street;
}

public void setStreet_number( String street_number ) {
this.street_number = street_number;
}

@Override
public String toString() {
return "AddressComponent [city=" + this.city + ", district="
+ this.district + ", province=" + this.province + ", street="
+ this.street + ", street_number=" + this.street_number + "]";
}

}
5
测试:
jsonString ( 目标json数据,已经在最上面写好的)
System.out.println( "jsonString:" + jsonString );
Gson gson = new Gson();
Result fromJson = gson.fromJson( jsonString.toString() ,
Result.class );
System.out.println( "******************************************" );
System.out.println( fromJson );
6
结果:
jsonString:{"status":0,"result":{"location":{"lng":103.98964143811,"lat":30.586643130352},"formatted_address":"四川省成都市双流县北一街154","business":"簇桥,金花桥","addressComponent":{"city":"成都市","district":"双流县","province":"四川省","street":"北一街","street_number":"154"},"cityCode":75}}
*******************************************
Result [status=0, result=ResultDetail [location=Location [lng=103.98964143811, lat=30.586643130352], formatted_address=四川省成都市双流县北一街154, addressComponent=AddressComponent [city=成都市, district=双流县, province=四川省, street=北一街, street_number=154], business=簇桥,金花桥, cityCode=75]]
7
可见,jsonString已经成功的被转换成了对应的javaBean
END
步骤3 : 总结.说明

Gson可以很轻松的实现javaBean和jsonString之间的互转.只需要明白json如何定义.剩下的就非常简单了.
推荐使用该框架,在网上看到过一篇解析json的各种方式的效率比较. Gsoon的效率是最高的.
再推荐一个jsonString格式化工具.那样能方便你的阅读-地址可以在参考资料中找到

4
当然上面的例子只是Gson的很小的一个用例,对于将javabean转换成jsonString,以及更为复杂的使用.请关注我后续经验