Android用Gson解析JSON字符串

在volley框架中有一个 protected Response<Result<T>> parseNetworkResponse(NetworkResponse response){}函数。从服务器上或者在缓存中获取的JSON字符串在这个函数进行解析。

String jsonString = new String(response.data, HttpHeaderParser.parseCharset(response.headers, HTTP.UTF_8))    
Result<T> result = GsonUtil.getResult(jsonString, mTypeToken);

我们可以定义一个GsonUtil类。里面写一些Gson和JSON相互转化的功能函数。例如上用到的getResult函数。利用该函数获取的Result<T>这个JavaBean。也就是返回的规范，该规范由前端开发人员和后台开发人员商量得出。既然得到的JavaBean，那么我再要获取JSON里面的数据就像从一个类中获取一个数据一样简单了。

public static <T> T getResult(String jsonData, TypeToken<T> type) {
        Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();
        return (T) gson.fromJson(jsonData, type.getType());
    }

Result<T>类：例如：（后台返回的JSON字符串形如：{"err":"success","errno":1,"rsm{"userId":"1","email":"?","password":"?","firstName":"胡","lastName":"安","gender":"1","photo":"/picture/userPhoto/1422624411423.PNG","autograph":"","introduce":"","createTime":"4天前"}}失败返回{"err":"用户不存在!",errno":0} ）

package whu.cn.whushare.bean;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Result<T> {
    @Expose
    @SerializedName("currentPage")
    private long currentPage;
    @Expose
    @SerializedName("pageSize")
    private long pageSize;
    @Expose
    @SerializedName("allDataCount")
    private long allDataCount;
    @Expose
    @SerializedName("nextPage")
    private long nextPage;
    @Expose
    @SerializedName("errno")
    private int code;
    @Expose
    @SerializedName("err")
    private String msg;
    private int total;
    @Expose
    @SerializedName("rsm")
    private T content;

    public Result(T result) {
        this.content = result;
    }

    public Result(int code, T result) {
        this.code = code;
        this.content = result;
    }

    public long getCurrentPage() {
        return currentPage;
    }

    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }

    public long getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public long getAllDataCount() {
        return allDataCount;
    }

    public void setAllDataCount(int allDataCount) {
        this.allDataCount = allDataCount;
    }

    public long getNextPage() {
        return nextPage;
    }

    public void setNextPage(int nextPage) {
        this.nextPage = nextPage;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public int getTotal() {
        return total;
    }

    public void setTotal(int total) {
        this.total = total;
    }

    public T getContent() {
        return content;
    }

    public void setContent(T content) {
        this.content = content;
    }
}