打造一个专注Java假数据的JBMock

作者: Android开发哥 | 来源:发表于2017-05-17 16:59 被阅读374次

前言

两个月前写过一篇文章基于Django设计的Restful MockServer，是基于网络的。很多人都觉得思路不错，但是主要是太麻烦了。本篇博文就根据Java开发一个假数据生成器，称为JBMock。

Github地址

主要功能

1、提供同步、异步获取数据
2、异步获取数据提供线程切换

原理图

1、使用反射，获取UserEntity的属性和对应注解(Type注解)
2、获取注解里面的值，然后使用TypeParser解析注解值，然后设置到对应的属性上
3、使用ThreadDispatcher完成回调

代码分析

包结构

代码

Type注解

package com.august1996.anno;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface Type {
    String value();
}

这个注解的意义在于我们给某个属性加上这个注解，然后根据类型去给属性赋值，例如value为username时，那么这个属性就会被赋上小明、小红、小花等值

TypeParser类型解析器

package com.august1996.core;

public interface TypeParser {
    Object parser(String type);
}

该接口的作用是解析Type注解的value，返回对应的值

OnMockedCallback回调

package com.august1996.callback;

import java.util.ArrayList;

public interface OnMockedCallback<T> {
    void onMocked(ArrayList<T> listEntity);
}

当异步模拟数据完成时，该回调带着结果被执行

ThreadDispatcher线程切换

package com.august1996.thread;

import java.util.ArrayList;

import com.august1996.callback.OnMockedCallback;

public interface ThreadDispatcher {
    <T> void dispatcher(ArrayList<T> value, OnMockedCallback<T> callback);
}

该接口完成回调时的线程切换，本项目是JavaSDK的，如果接入Android时，只需要继承自该接口使用Handler就能完成主线程切换

DefaultDispatcher分配默认线程

package com.august1996.thread;

import java.util.ArrayList;

import com.august1996.callback.OnMockedCallback;

public class DefaultDispatcher implements ThreadDispatcher {

    @Override
    public <T> void dispatcher(ArrayList<T> value, OnMockedCallback<T> callback) {
        if (callback != null) {
            callback.onMocked(value);
        }
    }

}

该类是最简单的ThreadDispatcher,如果需要在Android中切换主线程，只需要继承ThreadDispatcher，然后使用Handler切换回主线程就OK了

DispatcherHolder管理类

package com.august1996.thread;

import java.util.HashMap;
import java.util.Map;

public class DispatcherHolder {

    private static final Map<Class<? extends ThreadDispatcher>, ThreadDispatcher> sMap;

    static {
        sMap = new HashMap<>();
        register(new DefaultDispatcher());
    }

    public static void register(ThreadDispatcher dispatcher) {
        sMap.put(dispatcher.getClass(), dispatcher);
    }

    public static void unregister(Class<? extends ThreadDispatcher> clazz) {
        sMap.remove(clazz);
    }

    public static ThreadDispatcher get(Class<? extends ThreadDispatcher> clazz) {
        return sMap.get(clazz);
    }

}

该类的作用是管理不同类型的ThreadDispatcher，可以通过注册不同的ThreadDispatcher，使JBMock可以调用其他自己编写的ThreadDispatcher

ValueHolder类型数据管理器

package com.august1996.parser;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class ValueHolder {
    private static final Map<String, List<Object>> sMap = new HashMap<String, List<Object>>();
    private static final Random sRandom = new Random();

    public static void register(String type, Object... value) {
        List<Object> list = sMap.get(type);
        if (list == null) {
            list = new ArrayList<Object>();
            sMap.put(type, list);
        }
        list.addAll(Arrays.asList(value));
    }

    public static void unregister(String type) {
        sMap.remove(type);
    }

    public static void clear() {
        sMap.clear();
    }

    static Object get(String type) {
        List<Object> list = sMap.get(type);
        if (list != null && !list.isEmpty()) {
            return list.get(sRandom.nextInt(list.size()));
        }
        return null;
    }
}

该类负责管理Type注解对应的数据，例如如果想要当属性的Type的value为username时，JBMock就会给这个属性赋值小明、小红、小花等内容，那么就需要register("username","小明","小红","小花")

HolderParser解析器

package com.august1996.parser;

import com.august1996.core.TypeParser;

public class HolderParser implements TypeParser {

    @Override
    public Object parser(String type) {
        return ValueHolder.get(type);
    }

}

该类为默认的Parser之一，结合Type注解和ValueHolder根据类型解析数据

MockRunnable异步任务

package com.august1996.core;

import java.util.ArrayList;

import com.august1996.callback.OnMockedCallback;
import com.august1996.thread.DispatcherHolder;
import com.august1996.thread.ThreadDispatcher;

public class MockRunnable<T> implements Runnable {

    private Class<T> clazz;
    private int size;
    private int delay;
    private OnMockedCallback<T> callback;
    private Class<? extends ThreadDispatcher> threadDispatch;

    public MockRunnable(Class<T> clazz, int size, int delay, Class<? extends ThreadDispatcher> threadDispatch,
            OnMockedCallback<T> callback) {
        super();
        this.delay = delay;
        this.clazz = clazz;
        this.callback = callback;
        this.size = size;
        this.threadDispatch = threadDispatch;
    }

    @Override
    public void run() {
        try {
            Thread.sleep(delay);
            ArrayList<T> listEntity = Factory.getListEntity(clazz, size);
            DispatcherHolder.get(threadDispatch).dispatcher(listEntity, callback);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

}

Factory数据生产类

package com.august1996.core;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import com.august1996.anno.Type;
import com.august1996.parser.DefaultParser;
import com.august1996.parser.HolderParser;

public class Factory {
    static {
        mParser = new HashMap<>();
        initDefautParser();
    }
    private static Map<Class<? extends TypeParser>, TypeParser> mParser;

    /**
     * 获取多个Entity
     * 
     * @param cls
     *            Entity的类
     * @param size
     *            Entity的数量
     * @return
     */
    static <T> ArrayList<T> getListEntity(Class<T> cls, int size) {
        ArrayList<T> result = new ArrayList<T>();
        for (int i = 0; i < size; i++) {
            result.add(getEntity(cls));
        }
        return result;
    }

    /**
     * 获取单个Entity
     * 
     * @param cls
     * @return
     */
    static <T> T getEntity(Class<T> cls) {
        T obj = null;

        try {
            obj = cls.newInstance();

            Field[] declaredFields = cls.getDeclaredFields();
            for (Field field : declaredFields) { // 获取Entity类的所有属性
                field.setAccessible(true);
                Annotation[] annotations = field.getAnnotations(); // 获取属性的注解
                for (Annotation anno : annotations) {
                    if (anno instanceof Type) {
                        for (Map.Entry<Class<? extends TypeParser>, TypeParser> parser : mParser.entrySet()) {
                            Object value = parser.getValue().parser(((Type) anno).value()); // 获取到Type注解，使用TypeParser去解析类型
                            if (value != null) {
                                field.set(obj, value);
                            }
                        }
                    }
                }
            }

        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return obj;
    }

    /**
     * 初始化默认TypeParser
     */
    private static void initDefautParser() {
        addParser(new HolderParser());
    }

    public static void addParser(TypeParser typeParser) {
        mParser.put(typeParser.getClass(), typeParser);
    }

    public static TypeParser removeParser(Class<? extends TypeParser> clazz) {
        return mParser.remove(clazz);
    }

    public static void clearParser() {
        mParser.clear();
        initDefautParser();
    }
}

该类主要是用来产生数据

JBMock核心类

package com.august1996.core;

import java.util.ArrayList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.august1996.callback.OnMockedCallback;
import com.august1996.thread.ThreadDispatcher;

public class JBMock {
    private static final JBMock sInstance = new JBMock();

    public static JBMock getInstance() {
        return sInstance;
    }

    private JBMock() {
        mExecutors = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
    }

    private ExecutorService mExecutors;

    public <T> ArrayList<T> syncGet(Class<T> cls, int delay, int size) {
        try {
            Thread.sleep(delay);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return Factory.getListEntity(cls, size);
    }


    public <T> void asyncGet(Class<T> cls, int delay, int size, Class<? extends ThreadDispatcher> threadDispatcherCls,
            OnMockedCallback<T> callback) {
        mExecutors.submit(new MockRunnable<T>(cls, size, delay, threadDispatcherCls, callback));
    }


}

使用

新建一个UserEntity

package com.august1996.test;

import com.august1996.anno.Type;
import com.august1996.parser.DefaultType;

public class UserEntity {
    @Type("username")
    public String username;
    @Type("icon")
    public String icon;
    @Type("gender")
    public int gender;
    @Type(DefaultType.NOW_TIMESTAMP)
    public long regTime;

    @Override
    public String toString() {
        return "UserEntity [username=" + username + ", icon=" + icon + ", gender=" + gender + ", regTime=" + regTime
                + "]";
    }

}

测试代码

package com.august1996.test;

import java.util.ArrayList;

import com.august1996.callback.OnMockedCallback;
import com.august1996.core.JBMock;
import com.august1996.parser.ValueHolder;
import com.august1996.thread.DefaultDispatcher;

public class TestDemo {
    public static void main(String[] args) {
        ValueHolder.register("username", "小明", "小红");
        ValueHolder.register("username", "小花");

        ValueHolder.register("icon", "http://www.baidu.com/1.jpg", "http://www.baidu.com/2.jpg");
        ValueHolder.register("icon", "http://www.baidu.com/3.jpg");

        ValueHolder.register("gender", 1);
        ValueHolder.register("gender", 0);

        ArrayList<UserEntity> list = JBMock.getInstance().syncGet(UserEntity.class, 3000, 10);
        for (UserEntity entity : list) {
            System.out.println(entity.toString());
        }

        JBMock.getInstance().asyncGet(UserEntity.class, 3000, 5, DefaultDispatcher.class,
                new OnMockedCallback<UserEntity>() {

                    @Override
                    public void onMocked(ArrayList<UserEntity> listEntity) {
                        System.out.println(Thread.currentThread().getName());
                        for (UserEntity entity : listEntity) {
                            System.out.println(entity.toString());
                        }
                    }
                });

    }
}

输出

pool-1-thread-1
UserEntity [username=小花, icon=http://www.baidu.com/2.jpg, gender=0, regTime=1495010339777]
UserEntity [username=小明, icon=http://www.baidu.com/3.jpg, gender=1, regTime=1495010339779]
UserEntity [username=小明, icon=http://www.baidu.com/3.jpg, gender=1, regTime=1495010339779]
UserEntity [username=小红, icon=http://www.baidu.com/3.jpg, gender=0, regTime=1495010339779]
UserEntity [username=小花, icon=http://www.baidu.com/2.jpg, gender=1, regTime=1495010339779]

DefaultType.NOW_TIMESTAMP是什么

这是我们自定义的一个TypeParser，我们使用Factory.addParser添加就OK啦。

DefaultParser

package com.august1996.parser;

import com.august1996.core.TypeParser;

public class DefaultParser implements TypeParser {

    @Override
    public Object parser(String type) {
        if (DefaultType.NOW_TIMESTAMP.equals(type)) {
            return System.currentTimeMillis();
        }
        return null;
    }
}

DefaultType

package com.august1996.parser;

public class DefaultType {
    public static final String NOW_TIMESTAMP = "jb_now";
}

可自行扩展的地方

需要更多的扩展，实现ThreadDispatcher和TypeParser即可。

打造一个专注Java假数据的JBMock

前言

主要功能

原理图

代码分析

包结构

代码

Type注解

TypeParser类型解析器

OnMockedCallback回调

ThreadDispatcher线程切换

DefaultDispatcher分配默认线程

DispatcherHolder管理类

ValueHolder类型数据管理器

HolderParser解析器

MockRunnable异步任务

Factory数据生产类

JBMock核心类

使用

新建一个UserEntity

测试代码

输出

DefaultType.NOW_TIMESTAMP是什么

DefaultParser

DefaultType

可自行扩展的地方

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