##使用gson解析json文件

**json的格式有两种：**

**1. {}类型，及数据用{}包含；**

**2. []类型，即数据用[]包含；**

下面用个例子，简单的介绍gson如何解析json,仅使用~

先发两个json 内容

1、最外层是{}

{    
        "resp": "ok",
        "result": {
            "date": "2013-4-19 16:55:58",
            "focus": [
                {
                    "summary": "简介",
                    "title": "标题",
                    "url": "http://www.ceshi.com"
                },
                {
                    "summary": "简介22",
                    "title": "标题22",
                    "url": "http://www.ceshi22.com"
                }
            ],
            "items": [
                {
                    "id": "11",
                    "name": "名称",
                    "price": "88.88"
                },
                {
                    "id": "22",
                    "name": "名称22",
                    "price": "100"
                }
            ]
        }    
    }

2、外层是[]

[    
        {
            "addr": "北京",
            "age": "22",
            "name": "zeng"
        },
        {
            "addr": "上海",
            "age": "20",
            "name": "zhang"
        },
        {
            "addr": "深圳",
            "age": "25",
            "name": "wang"
        }    
    ]

###**一、使用Gson,解析，关键的就是定义好JavaBean类对象**

1、***定义｛｝类型的JavaBean类***

Bean.java

public class Bean {  //若实现Serializable接口，则不用写下面的SerializedName("字段名")，但成员变量名称必须与json中一样
    //  @SerializedName("resp")  
    //  private String respone;//假如变量命名与解析数据不同，则加上@SerializedName("")  
    private String resp;  
    private Result result;  
    //....下面省略 set ,get

//resultBean类

Result.java

public class Result {    
        private String date;  
        private List<FocusItem> focus;  
        private List<Item> items;  
    }
FocusItem.java

public class FocusItem {        
        private String title;  
        private String summary;  
        private String url;  
    }
Item.java

public class Item {            
        private String name;  
        private int id;  
        private float price; 
    }

2、***定义｛｝类型的JavaBean类***

Info.java

public class Info {    
        private String name;  
        private int age;  
        private String addr; 
    }

###**二、解析代码，一个最外层是{}  一个是[]**

private void parse() {  
        Gson gson = new Gson();  
        switch (type) { 
        //最外层是{}，封装为一个对象
        case OBJ:  
            Bean fromJson = gson.fromJson(readContent, Bean.class);  
            System.out.println(fromJson.toString());  
            break;  
        //最外层是[]，封装为一个数组对象
        case ARR:  
            Type type = new TypeToken<List<Info>>() {}.getType();  
            Object fromJson2 = gson.fromJson(readContent, type);  
            List<Info> list = (List<Info>) fromJson2; 
            break; 
        }
    }