Java 小知识

1.Json引入jar包

<dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>

　　2.获取Json内容key的方法

JSONObject jsonArray=对应的jsonObject内容
Iterator it = jsonArray.keys();
        while (it.hasNext()) {
            String key = it.next().toString();
            String typeName =getType(jsonArray.get(key));
            String value = jsonArray.get(key).toString();
            System.out.println(“key=”+key);
            System.out.println("value="+value);
            System.out.println("value的类型="+typeName);
        }

　　3.获取Map的key的方法

Map<String,Objec> c = new HashMap<String,Objec>();
c.put("key1","value1");
c.put("key2","value2");
for(String key : c.keySet()){
　　Object value = c.get(key);
　　String typeName =getType(c.get(key));
　　System.out.println(key+"  "+value);
}

　　4。

4.Java String和List<Object>之间的转换:需要引入：

import com.fasterxml.jackson.core.type.TypeReference;

ObjectMapper mapper = new ObjectMapper();
List<Object> list = mapper.readValue(str,
                    new TypeReference<List<Object>>() {});