Hutool开发利器MapProxy类使用技巧详解

@Test
public void testMapProxy1() {
    Map<String, Object> userMap = MapUtil.newHashMap(16);
    userMap.put("username", "alvin");
    userMap.put("age", 20);
    // 使用map的时候, 需要进行强转，一旦类型错误，会报错
    String age = (String)userMap.get("age");
}

<dependency>
  <groupId>cn.hutool</groupId>
  <artifactId>hutool-all</artifactId>
  <version>5.8.8</version>
</dependency>

interface MapUser {
    String getUsername();
    Integer getAge();
    MapUser setAge(Integer age);
}

@Test
public void testMapProxy2() {
    Map<String, Object> userMap = MapUtil.newHashMap(16);
    userMap.put("username", "alvin");
    userMap.put("age", 20);
    MapProxy mapProxy = MapProxy.create(userMap);
    Integer age = mapProxy.getInt("age", 18);
    Assert.assertTrue(age == 20);
    // 通过代理的方式
    MapUser mapUser = mapProxy.toProxyBean(MapUser.class);
    // 后续访问会变的更加安全
    Assert.assertTrue(mapUser.getAge() == 20);
    mapUser.setAge(30);
    Assert.assertTrue(mapUser.getAge() == 30);
}

public <T> T toProxyBean(Class<T> interfaceClass) {
    return (T) Proxy.newProxyInstance(ClassLoaderUtil.getClassLoader(), new Class<?>[]{interfaceClass}, this);
}

public Object invoke(Object proxy, Method method, Object[] args) {
    final Class<?>[] parameterTypes = method.getParameterTypes();
    // 如果调用方法参数为空
    if (ArrayUtil.isEmpty(parameterTypes)) {
        final Class<?> returnType = method.getReturnType();
        // 方法返回值不是void
        if (void.class != returnType) {
            // 匹配Getter
            final String methodName = method.getName();
            String fieldName = null;
            if (methodName.startsWith("get")) {
                // 匹配getXXX
                fieldName = StrUtil.removePreAndLowerFirst(methodName, 3);
            } else if (BooleanUtil.isBoolean(returnType) && methodName.startsWith("is")) {
                // 匹配isXXX
                fieldName = StrUtil.removePreAndLowerFirst(methodName, 2);
            }else if ("hashCode".equals(methodName)) {
                return this.hashCode();
            } else if ("toString".equals(methodName)) {
                return this.toString();
            }
            if (StrUtil.isNotBlank(fieldName)) {
                if (false == this.containsKey(fieldName)) {
                    // 驼峰不存在转下划线尝试
                    fieldName = StrUtil.toUnderlineCase(fieldName);
                }
                return Convert.convert(method.getGenericReturnType(), this.get(fieldName));
            }
        }
        // 如果方法参数不为空
    } else if (1 == parameterTypes.length) {
        // 匹配Setter
        final String methodName = method.getName();
        if (methodName.startsWith("set")) {
            final String fieldName = StrUtil.removePreAndLowerFirst(methodName, 3);
            if (StrUtil.isNotBlank(fieldName)) {
                this.put(fieldName, args[0]);
                final Class<?> returnType = method.getReturnType();
                // 判断返回类型是不是代理类的实例
                if(returnType.isInstance(proxy)){
                    return proxy;
                }
            }
        } else if ("equals".equals(methodName)) {
            return this.equals(args[0]);
        }
    }
    throw new UnsupportedOperationException(method.toGenericString());
}