java - 数组列表

Question

I am trying to return JSON data with my restlet. I can return a single item's JSON with..

import org.json.JSONObject;

Site aSite = new Site().getSite();   
JSONObject aSiteJson = new JSONObject(aSite);
return aSiteJson.toString();

Returns: {"name":"qwerty","url":"www.qwerty.com"}

How do i return JSON for ArrayList Object

ArrayList<Site> allSites = new SitesCollection().getAllSites();   
JSONObject allSitesJson = new JSONObject(allSites);
return allSitesJson.toString();

Returns: {"empty":false}

ArrayList<Site> allSites = new SitesCollection().getAllSites();   
JSONArray allSitesJson = new JSONArray(allSites);
return allSitesJson.toString();

Returns: ["com.sample.Site@4a7140","com.sample.Site@1512c2e","com.sample.Site@2bba21","com.sample.Site@c8d0b7"]

Here is my Site class

public class Site {
private String name;
private String url;

public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getUrl() {
    return url;
}
public void setUrl(String url) {
    this.url = url;
}

public Site(String name, String url) {
    super();
    this.name = name;
    this.url = url;
}       

}

Thanks

score 8 · Accepted Answer

You coud use Gson library, that handles lists properly, instead.

Usage example:

class BagOfPrimitives {
    private int value1;
    private String value2;
    private transient int value3;
    public BagOfPrimitives(int value1, String value2, int value3) {
        this.value1 = value1;
        this.value2 = value2;
        this.value3 = value3;
    }
}

BagOfPrimitives obj1 = new BagOfPrimitives(1, "abc", 3);
BagOfPrimitives obj2 = new BagOfPrimitives(32, "gawk", 500);
List<BagOfPrimitives> list = Arrays.asList(obj1, obj2);
Gson gson = new Gson();
String json = gson.toJson(list);  
// Now json is [{"value1":1,"value2":"abc"},{"value1":32,"value2":"gawk"}]

score 1 · Accepted Answer

1

You could override the toString method in your Site class to return new JSONObject(this).toString

于 2012-10-11T22:11:20.573 回答

score 0 · Accepted Answer

here is my solution using simple-json.

JSONArray jr = new JSONArray();
for (int x = 1; x <= number_of_items; x++)
    {
        JSONObject obj = new JSONObject();
        obj.put("key 1", 10);
        obj.put("key 2", 20);
        jr.add(obj);

    }
System.out.print(jr);

Output:

[{"key 1":10,"key 2":20},{"key 1":10,"key 2":20}]

score 0 · Accepted Answer

您必须将数组的每个项目添加为 JSONObject 作为数组列表的索引

循环遍历您的数组列表，创建 jsonobjects，其中 Site 对象的每个元素都是 jsonobject 中的键值对

然后将该 jsonobject 添加到您的 jsonarray 的索引中

for(int i = 0; i < allsites.length(); i++){
    ...
}

4 回答 4

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