将HashMap的ArrayList转换为JSON字符串

比眉伴天荒 2023-09-30 09:51 11阅读 0赞

有很多方法可以实现这一目标。我将解释两种方式：

### 你可以这样做： ###

package hashmaparraylistjson;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import org.json.JSONArray;
    import org.json.JSONObject;
    
    public class HashMapArrayListJSON {
    
        public static void main(String[] args) {
            ArrayList<HashMap<String, String>> dataMap = new ArrayList<HashMap<String, String>>();
    
            HashMap<String, String> data1 = new HashMap<String, String>();
            data1.put("image", "2130837526");
            data1.put("category", "Chairs");
            data1.put("Quantity", "1");
    
            HashMap<String, String> data2 = new HashMap<String, String>();
            data2.put("image", "2130837566");
            data2.put("category", "Mirrors");
            data2.put("Quantity", "2");
    
            dataMap.add(data1);
            dataMap.add(data2);
    
            List<JSONObject> jsonObj = new ArrayList<JSONObject>();
    
            for (HashMap<String, String> data : dataMap) {
                JSONObject obj = new JSONObject(data);
                jsonObj.add(obj);
            }
    
            JSONArray test = new JSONArray(jsonObj);
    
            System.out.println(test.toString());
        }
    
    }

--------------------

### 或者您可以使用杰克逊对象映射器： ###

[下载杰克逊核心][Link 1]

[下载杰克逊映射器][Link 2]

### 将外部库添加到 Eclipse 项目 ###

> [将库/JAR 添加到 Eclipse Android 项目][JAR _ Eclipse Android]

### Java 代码 ###

package hashmaparraylistjson;
    
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import java.util.ArrayList;
    import java.util.HashMap;
    
    public class HashMapArrayListJSON {
    
        public static void main(String[] args) throws JsonProcessingException {
            ArrayList<HashMap<String, String>> dataMap = new ArrayList<HashMap<String, String>>();
    
            HashMap<String, String> data1 = new HashMap<String, String>();
            data1.put("image", "2130837526");
            data1.put("category", "Chairs");
            data1.put("Quantity", "1");
    
            HashMap<String, String> data2 = new HashMap<String, String>();
            data2.put("image", "2130837566");
            data2.put("category", "Mirrors");
            data2.put("Quantity", "2");
    
            dataMap.add(data1);
            dataMap.add(data2);
    
            ObjectMapper objectMapper = new ObjectMapper();
    
            String json = objectMapper.writeValueAsString(dataMap);
    
            System.out.println(json);
        }
    
    }

两个选项都将打印：

[{"image":"2130837526","category":"Chairs","Quantity":"1"},{"image":"2130837566","category":"Mirrors","Quantity":"2"}]

[Link 1]: http://central.maven.org/maven2/org/codehaus/jackson/jackson-core-asl/1.9.13/jackson-core-asl-1.9.13.jar
[Link 2]: http://central.maven.org/maven2/org/codehaus/jackson/jackson-mapper-asl/1.9.13/jackson-mapper-asl-1.9.13.jar
[JAR _ Eclipse Android]: https://stackoverflow.com/questions/3642928/adding-a-library-jar-to-an-eclipse-android-project/3643015