add keywords

data/2.Java中阶/4.网络编程/4.Java的基本网络支持/Support.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "Support.md",
+  "exercise_id": "eac8c5c2b7b14122bdd66651e40169a5",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/4.网络编程/4.Java的基本网络支持/Support.md

+# Java基本网络支持
+
+
+下列对于Java网络支持的相关说法错误的是：
+
+
+## 答案
+
+```
+URI是统一资源标识符，可以用来定位资源
+```
+
+## 选项
+
+### A
+
+```
+InetAddress类有两个子类：Inet4Address和Inet6Address
+```
+
+### B
+
+```
+URLDecoder和URLEncoder用于完成普通字符串和MIME字符串之间的相互转换
+```
+
+### C
+
+```
+URL是统一资源定位器
+```

data/2.Java中阶/4.网络编程/4.Java的基本网络支持/config.json

+{
+  "node_id": "java-1e8ef0cdeec443d8addaaa79b760c6b1",
+  "keywords": ["network"],
+  "children": [
+    {
+      "使用URLDecoder和URLEncoder": {
+        "keywords": [],
+        "children": [],
+        "node_id": "java-f880ae75add64feaae9a85ea7c9367b2",
+        "title": "使用URLDecoder和URLEncoder"
+      }
+    },
+    {
+      "URL、URLConnection和URLPermission": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
+        "title": "URL、URLConnection和URLPermission"
+      }
+    }
+  ],
+  "export": ["Support.json"],
+  "title": "Java的基本网络支持"
+}
\ No newline at end of file

data/2.Java中阶/4.网络编程/5.使用代理服务器/Proxy.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "Proxy.md",
+  "exercise_id": "9ab4eaf561144775b08bf657416721af",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/4.网络编程/5.使用代理服务器/Proxy.md

+# Proxy
+
+
+下列对http请求使用代理的方式正确的是：
+
+
+## 答案
+
+```
+以上选择均正确
+```
+
+## 选项
+
+### A
+
+```java
+// 在你发起Http请求之前设置代理属性
+Properties prop = System.getProperties();
+prop.setProperty("http.proxyHost",  proxyHost);
+prop.setProperty("http.proxyPort",  proxyPort);
+```
+
+### B
+
+```java
+// 通过Proxy来配置代理信息
+URL url = new URL("http://www.baidu.com");
+Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort)); 
+URLConnection conn = url.openConnection(proxy);
+```
+
+### C
+
+```java
+// httpclient设置代理
+HttpClient client = HttpClient.newBuilder()
+                .version(HttpClient.Version.HTTP_2)
+                .connectTimeout(Duration.ofSeconds(10))
+                .proxy(ProxySelector.of(new InetSocketAddress(proxyHost, proxyHost)))
+                .build();
+```

data/2.Java中阶/4.网络编程/5.使用代理服务器/config.json

+{
+  "node_id": "java-cb9fdf69e28f40aca9ef741b9c8bc925",
+  "keywords": ["network", "proxy"],
+  "children": [
+    {
+      "直接使用Proxy创建连接": {
+        "keywords": [],
+        "children": [],
+        "node_id": "java-367580927af845268b72979f1e1e16be",
+        "title": "直接使用Proxy创建连接"
+      }
+    },
+    {
+      "使用ProxySelector自动选择代理服务器": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
+        "title": "使用ProxySelector自动选择代理服务器"
+      }
+    }
+  ],
+  "export": ["Proxy.json"],
+  "title": "使用代理服务器"
+}
\ No newline at end of file

data/2.Java中阶/4.网络编程/6.Java 11标准化的HTTP Client/HTTPClient.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "HTTPClient.md",
+  "exercise_id": "c5456368050f4ad1bdce9e19548e5c1a",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/4.网络编程/6.Java 11标准化的HTTP Client/HTTPClient.md

+# HTTPClient
+
+
+下列语句皆为使用HTTPClient获取网页的流程之一，其中不正确的是：
+
+
+## 答案
+
+```java
+HttpResponse.BodyHandler<String> bodyHandler = HttpResponse.BodyHandlers;
+```
+
+## 选项
+
+### A
+
+```java
+String url = "https://www.baidu.com";
+HttpClient client = HttpClient.newBuilder().build();
+```
+
+### B
+
+```java
+HttpRequest request = HttpRequest.newBuilder()
+                .uri(URI.create(url))
+                .header("Content-Type", "text/html")
+                .GET()
+                .build();
+```
+
+### C
+
+```java
+HttpResponse<String> response = client.send(request, bodyHandler);
+if (response.statusCode() == 200) {
+    System.out.println(response.body());
+}
+```

data/2.Java中阶/4.网络编程/6.Java 11标准化的HTTP Client/WebSocket.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "WebSocket.md",
+  "exercise_id": "dac563065d504db1bdca92dba611f4cb",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/4.网络编程/6.Java 11标准化的HTTP Client/WebSocket.md

+# WebSocket
+
+
+`WebSocket`可以实现服务端对客户端的推送，避免客户端轮询，造成带宽资源浪费。以下关于`WebSocket`的说法错误的是：
+
+
+## 答案
+
+```
+WebSockt与HTTP都是基于TCP的，因此url也是以HTTP开头
+```
+
+## 选项
+
+### A
+
+```
+WebSocket基于TCP协议
+```
+
+### B
+
+```
+WebSocket是双向的，即全双工协议
+```
+
+### C
+
+```
+WebSocket是一种有状态的协议
+```

data/2.Java中阶/4.网络编程/6.Java 11标准化的HTTP Client/config.json

+{
+  "node_id": "java-dd60957a0a7f4155a68aea7c6807d504",
+  "keywords": ["websocket", "get", "post", "delete", "put", "请求"],
+  "children": [
+    {
+      "发送同步GET请求": {
+        "keywords": [],
+        "children": [],
+        "node_id": "java-01931200f6684a0bba54c8fe79070301",
+        "title": "发送同步GET请求"
+      }
+    },
+    {
+      "发送带请求体的请求": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
+        "title": "发送带请求体的请求"
+      }
+    },
+    {
+      "发送异步请求": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
+        "title": "发送异步请求"
+      }
+    },
+    {
+      "WebSocket客户端支持": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "基于WebSocket的多人实时聊天": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    }
+  ],
+  "export": ["HTTPClient.json", "WebSocket.json"],
+  "title": "Java 11标准化的HTTP Client"
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/3.instanceof与Class的等价性/Instanceof.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "Instanceof.md",
+  "exercise_id": "d2b56cc9a32a4b9993ab41bad65892b2",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/3.instanceof与Class的等价性/Instanceof.md

+# Instanceof
+
+
+已知Person是Man的父类，以下结果为True的是：
+
+## aop
+
+### before
+
+```java
+Man man = new Man();
+Person person = new Person();
+```
+
+## 答案
+
+```
+man instanceof Person
+```
+
+## 选项
+
+### A
+
+```java
+man.getClass.equals(Person.class)
+```
+
+### B
+
+```java
+Man.class.isInstance(person)
+```
+
+### C
+
+```java
+person.getClass() == Man.class
+```

data/2.Java中阶/5.类型信息/3.instanceof与Class的等价性/config.json

+{
+  "node_id": "java-feca89c3fb9e4bcaba3f1f95e8ad4753",
+  "keywords": ["类型"],
+  "children": [],
+  "export": ["Instanceof.json"],
+  "title": "instanceof与Class的等价性"
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/4.反射：运行时类信息/Reflect.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "Reflect.md",
+  "exercise_id": "a37be7bf155943179abd1d1c3efb7064",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/4.反射：运行时类信息/Reflect.md

+# Reflect
+
+
+下列关于JAVA反射的说法正确的是：
+
+## aop
+
+### before
+
+```java
+
+```
+
+## 答案
+
+```
+以上说法均正确
+```
+
+## 选项
+
+### A
+
+```
+反射机制作用在程序运行状态
+```
+
+### B
+
+```
+能动态获取类的属性及方法并能进行调用
+```
+
+### C
+
+```
+反射首先要获取类的Class类对象
+```

data/2.Java中阶/5.类型信息/4.反射：运行时类信息/ReflectTest.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "ReflectTest.md",
+  "exercise_id": "23057a3a31b0428e8ed7c44b5328d48a",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/4.反射：运行时类信息/ReflectTest.md

+# ReflectTest
+
+
+以下程序是关于反射的一个例子，程序的控制台打印为：
+```java
+public class Reflect {
+    public static void main(String[] args) throws NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException {
+        Class clazz = Student.class;
+        Constructor con = clazz.getConstructor(String.class, Integer.class);
+        Student student1 = (Student) con.newInstance("小铭", 24);
+        Student student2 = new Student("小铭", 24);
+        System.out.println(student2 == student1);
+        System.out.println(student2.equals(student1));
+    }
+}
+```
+
+## aop
+
+### before
+
+```java
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+
+class Student {
+    private String name;
+    private Integer age;
+
+    public Student() {}
+
+    public Student(String name, Integer age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                '}';
+    }
+}
+```
+
+## 答案
+
+```
+false
+false
+```
+
+## 选项
+
+### A
+
+```
+false
+true
+```
+
+### B
+
+```
+true
+false
+```
+
+### C
+
+```
+true
+true
+```

data/2.Java中阶/5.类型信息/4.反射：运行时类信息/config.json

+{
+  "node_id": "java-42b26ca8a2384dcfb02fca6e159ace67",
+  "keywords": ["annotation", "标注"],
+  "children": [
+    {
+      "类方法抽取器": {
+        "keywords": [],
+        "children": [],
+        "node_id": "java-aa383e03d51a4ea588ee1b04192ab556",
+        "title": "类方法抽取器"
+      }
+    },
+    {
+      "Class类与Java反射": {
+        "keywords": [],
+        "children": [
+          {
+            "访问构造方法": {
+              "keywords": [],
+              "children": [],
+              "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
+              "title": "访问构造方法"
+            }
+          },
+          {
+            "访问成员变量": {
+              "keywords": [],
+              "children": [],
+              "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+            }
+          },
+          {
+            "访问方法": {
+              "keywords": [],
+              "children": [],
+              "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+            }
+          }
+        ],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
+        "title": "Class类与Java反射"
+      }
+    },
+    {
+      "使用Annotation功能": {
+        "keywords": [],
+        "children": [
+          {
+            "定义Annotation类型": {
+              "keywords": [],
+              "children": [],
+              "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+            }
+          },
+          {
+            "访问Annotation信息": {
+              "keywords": [],
+              "children": [],
+              "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+            }
+          }
+        ],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "声明异常入门": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "资源": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "利用反射分析类的能力": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "使用反射在运行时分析": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "使用反射编写泛型数组": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "访问字段": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "调用方法": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "调用构造方法": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    },
+    {
+      "获取继承关系": {
+        "keywords": [],
+        "children": [],
+        "node_id": "569d5e11c4fc5de7844053d9a733c5e8"
+      }
+    }
+  ],
+  "export": ["Reflect.json", "ReflectTest.json"],
+  "title": "反射：运行时类信息"
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/5.动态代理/DynamicProxy.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "DynamicProxy.md",
+  "exercise_id": "3825ea2504a34a1fbd3f40090cb7a6ca",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/5.动态代理/DynamicProxy.md

+# DynamicProxy
+
+
+下列关于JAVA动态代理的说法正确的是：
+
+
+
+## 答案
+
+```
+以上说法均正确
+```
+
+## 选项
+
+### A
+
+```
+为对象提供一个代理，控制对对象的访问
+```
+
+### B
+
+```
+动态代理有两种实现方式：JDK动态代理实现和CGlib字节码技术实现
+```
+
+### C
+
+```
+JDK动态代理只能代理接口而不能代理类
+```

data/2.Java中阶/5.类型信息/5.动态代理/DynamicProxyTest.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "DynamicProxyTest.md",
+  "exercise_id": "675c2c4dcb41423095d3f6dcdae93aab",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/5.动态代理/DynamicProxyTest.md

+# DynamicProxyTest
+
+
+以下程序是关于动态代理的一个例子，1和2处填入正确的是：
+```java
+
+interface Person {
+    void speak(String text);
+}
+
+public class DynamicProxyTest {
+    public static void main(String[] args) {
+        InvocationHandler handler = new InvocationHandler() {
+            @Override
+            public Object invoke(Object proxy, Method method, Object[] args) {
+                if (method.getName().equals("speak")) {
+                    System.out.println("准备");
+                    System.out.println(args[0]);
+                    System.out.println("结束");
+                }
+                return null;
+            }
+        };
+        Person person = (Person) Proxy.newProxyInstance(
+                1,
+                2,
+                handler);
+        person.speak("你好，很高兴认识你。");
+    }
+}
+```
+
+
+## 答案
+
+```
+Person.class.getClassLoader()
+new Class[] { Person.class }
+```
+
+## 选项
+
+### A
+
+```
+Person.getClassLoader()
+Person.class
+```
+
+### B
+
+```
+Person.class.getClassLoader()
+Person.getClass()
+```
+
+### C
+
+```
+Person.getClassLoader()
+new Class[] { Person.class }
+```

data/2.Java中阶/5.类型信息/5.动态代理/config.json

+{
+  "node_id": "java-f7be740717c442c4a489a8c8d675f38c",
+  "keywords": ["proxy"],
+  "children": [],
+  "export": ["DynamicProxy.json", "DynamicProxyTest.json"],
+  "title": "动态代理"
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/6.空对象/None.json

+{
+  "type": "code_options",
+  "author": "clong",
+  "source": "None.md",
+  "exercise_id": "669d00b9f4c6408db09e5eeead918286",
+  "notebook_enable": true
+}
\ No newline at end of file

data/2.Java中阶/5.类型信息/6.空对象/None.md

+# 空对象
+
+
+下列关于空对象的说法错误的是：
+
+
+
+## 答案
+
+```
+构造空对象是java内置的
+```
+
+## 选项
+
+### A
+
+```
+空对象，没有赋值过，但是却在内存中存在
+```
+
+### B
+
+```
+空对象能避免报空指针异常
+```
+
+### C
+
+```
+有时候还是要判断对象是否为空对象
+```

data/2.Java中阶/5.类型信息/6.空对象/config.json

+{
+  "node_id": "java-dec42155c7904f7e9d00a37b5013470d",
+  "keywords": ["空对象"],
+  "children": [
+    {
+      "模拟对象与桩": {
+        "keywords": [],
+        "children": [],
+        "node_id": "java-0109d4ae23934645bc817fd2ac423854",
+        "title": "模拟对象与桩"
+      }
+    }
+  ],
+  "export": ["None.json"],
+  "title": "空对象"
+}
\ No newline at end of file