JSONObject和URL以及HttpURLConnection的使用

1 将java对象类转成json格式

首先引入依赖jar文件

注意依赖文件的版本号，高版本可能没有对应的类

2 我的实体类中包含内部类注意内部类要public才能被序列化成json格式

import java.util.List;

public class EuityParam {

    public EuityParam(String filter,List<String> args)
    {
        super();
        this.filter=new Param0(filter);
        this.args=new Param1(args);
    }

    private Param1 args;
    
    public Param1 getArgs()
    {
        return args;
    }
    public void setArgs(Param1 _Param1)
    {
        this.args=_Param1;
    }
    
    private Param0 filter;
    
    public Param0 getFilter()
    {
        return filter;
    }
    public void setFilter(Param0 _param0)
    {
        this.filter=_param0;
    }
    public class Param1
    {
        public List<String> getNameList() {
            return nameList;
        }
        public void setNameList(List<String> nameList) {
            this.nameList = nameList;
        }
        public Param1(List<String> nameList)
        {
            this.nameList=nameList;
        }
        private List<String> nameList;
        
        
    }
    public class Param0
    {
        public Param0(String key)
        {
            this.key=key;
        }
        private String key;
        
        public String getKey() 
        {
            return key;
        }
        public void setKey(String key)
        {
            this.key=key;
        }
    }
    
    
}

3 导入包文件

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

4 序列化

        List<String> nameLst=new LinkedList<String>();
        nameLst.add("AIR PRODUCTS & CHEMICALS INC");
        nameLst.add("AMAZON.COM INC");
        nameLst.add("ALTRIA GROUP INC");
        nameLst.add("APPLE INC");
        nameLst.add("ALPHABET INC");
        EuityParam euityParam=new EuityParam("EquityNameMatching", nameLst);
        
        JSONObject jsonData= JSONObject.fromObject(euityParam);
        System.out.println(jsonData);

5 结果：

{
    "args": {
        "nameList": [
            "AIR PRODUCTS & CHEMICALS INC",
            "AMAZON.COM INC",
            "ALTRIA GROUP INC",
            "APPLE INC",
            "ALPHABET INC"
        ]
    },
    "filter": {
        "key": "EquityNameMatching"
    }
}

6 接口的调用，这个调用是post

private static String doPost(URL url, Map<Object, Object> nameValuePairs, String userAgent, int redirescts)
            throws IOException {
        // TODO Auto-generated method stub
        StringBuilder response = new StringBuilder();
        // HttpURLConnection可以处理重定向
        HttpURLConnection connect = (HttpURLConnection) url.openConnection();
        if (userAgent != null) {
            connect.setRequestProperty("Authorization", userAgent);//设置http请求头
        }
        if (redirescts >= 0) {
            // 连接到服务器之前关闭自动重定向
            connect.setFollowRedirects(false);
        }
        // 设置请求的输出流
        connect.setDoOutput(true);
        // 构建往请求body内写入请求数据的写入流
        OutputStream out = connect.getOutputStream();
        try (PrintWriter write = new PrintWriter(out)) {
            boolean first = true;
            for (Entry<Object, Object> pair : nameValuePairs.entrySet()) {
                if (first) {
                    first = false;
                } else {
                    write.print('&');
                }
                String name = pair.getKey().toString();
                String value = pair.getValue().toString();
                write.print(name);
                write.print('=');
                write.print(URLEncoder.encode(value, "UTF-8"));
            }
        }

        // 获取请求的编码类型
        String encoding = connect.getContentEncoding();
        if (encoding == null) {
            encoding = "UTF-8";
        }

        // 如果redirect大于0表明有重定向
        if (redirescts > 0) {
            // 获取请求的响应码
            int responseCode = connect.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_MOVED_PERM || responseCode == HttpURLConnection.HTTP_MOVED_TEMP
                    || responseCode == HttpURLConnection.HTTP_SEE_OTHER) {

                // 获取重定向的位置
                String location = connect.getHeaderField("Location");
                if (location != null) {
                    java.net.URL base = connect.getURL();
                    // 断开本次连接
                    connect.disconnect();
                    return doPost(new URL(base, location), nameValuePairs, userAgent, redirescts - 1);
                }
            }
        } else if (redirescts == 0) {
            throw new IOException("重定向太多无法处理");
        }

        // 获取响应流
        InputStream responseStream = connect.getInputStream();
        try (Scanner in = new Scanner(responseStream, encoding)) {
            while (in.hasNextLine()) {
                response.append(in.nextLine());
                response.append("\n");
            }
        } 
        catch (Exception e) 
        {
            // TODO: handle exception
            InputStream err = connect.getErrorStream();
            if (err == null) {
                throw e;
            }
            try (Scanner in = new Scanner(err)) {
                response.append(in.hasNextLine());

            }
        }
        return response.toString();
    }