java.net 基本测试

java.net 基本测试

包

java.net

java.net.ssl

类

java.net.URL

测试类

package com.mozq.boot.kuayu01.demo;

import java.net.MalformedURLException;
import java.net.URL;

public class URL_01 {
    public static void main(String[] args) {
        try {
            URL url = new URL("");
            /*
            java.net.MalformedURLException: no protocol:
                at java.net.URL.<init>(URL.java:593)
                at java.net.URL.<init>(URL.java:490)
                at java.net.URL.<init>(URL.java:439)
             */

            URL url = new URL(null);
            /*
            java.net.MalformedURLException
                at java.net.URL.<init>(URL.java:627)
                at java.net.URL.<init>(URL.java:490)
                at java.net.URL.<init>(URL.java:439)
                at com.mozq.boot.kuayu01.demo.URL_01.main(URL_01.java:10)
            Caused by: java.lang.NullPointerException
                at java.net.URL.<init>(URL.java:532)
                ... 3 more
             */
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }
}

package com.mozq.boot.kuayu01.demo;

import com.alibaba.fastjson.JSONObject;

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

public class URL_02 {
    public static void main(String[] args) throws IOException {
        //URL url = new URL("http://localhost:9001/demo/name");
        URL url = new URL("http://www.baidu.com");
        URLConnection conn = url.openConnection();
        conn.setDoInput(true);
        conn.connect();

        //读取输入流
        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        StringBuilder result = new StringBuilder();
        String line = null;
        while((line = reader.readLine()) != null){
            result.append(line);
        }
        String s = result.toString();
        System.out.println(s);
    }
}

@RestController
@RequestMapping("/demo")
public class DemoController {
    @RequestMapping("/name")
    public String name(HttpServletResponse response){
        return "测试数据";
    }
}

异常

Exception in thread "main" java.net.ProtocolException: cannot write to a URLConnection if doOutput=false - call setDoOutput(true)

java.net.MalformedURLException: no protocol: