多线程运行上下文设计模式

Posted 2021-03-18 zheaven

设计思路：保证每个线程中共享资源的独立性

ExecutionTask

package com.dwz.concurrency2.chapter11;

public class ExecutionTask implements Runnable {
    
    private QueryFromDBAction queryaction = new QueryFromDBAction();
    private QueryFromHttpAction httpAction = new QueryFromHttpAction();
    
    @Override
    public void run() {
        final Context context = new Context();
        queryaction.execute(context);
        System.out.println("The name query successful.");
        httpAction.execute(context);
        System.out.println("The card id query successful.");
        System.out.println("The name is " + context.getName() + " and cardId is " + context.getCardId());
    }
}

QueryFromDBAction业务逻辑执行者1

package com.dwz.concurrency2.chapter11;

public class QueryFromDBAction {
    
    public void execute(Context context) {
        try {
            Thread.sleep(1000L);
            String name = "Alex " + Thread.currentThread().getName();
            context.setName(name);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

QueryFromHttpAction业务逻辑执行者2

package com.dwz.concurrency2.chapter11;

public class QueryFromHttpAction {
    
    public void execute(Context context) {
        String name = context.getName();
        String cardId = getCardId(name);
        context.setCardId(cardId);
    }
    
    private String getCardId(String name) {
        try {
            Thread.sleep(1000L);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "4464643@@" + Thread.currentThread().getId();
    }
}

Context共享资源

package com.dwz.concurrency2.chapter11;

public class Context {
    private String name;
    private String cardId;
    
    public void setName(String name) {
        this.name = name;
    }
    
    public String getName() {
        return this.name;
    }

    public void setCardId(String cardId) {
        this.cardId = cardId;
    }

    public String getCardId() {
        return cardId;
    }
}

测试

package com.dwz.concurrency2.chapter11;

import java.util.stream.IntStream;

public class ContextTest {
    public static void main(String[] args) {
        IntStream.range(1, 5).forEach(i -> new Thread(new ExecutionTask()).start());
    }
}

使用ThreadLocal来实现线程上下文设计模式，实现线程之间的隔离

ExecutionTask

package com.dwz.concurrency2.chapter12;

public class ExecutionTask implements Runnable {
    
    private QueryFromDBAction queryaction = new QueryFromDBAction();
    private QueryFromHttpAction httpAction = new QueryFromHttpAction();
    
    @Override
    public void run() {
        queryaction.execute();
        System.out.println("The name query successful.");
        httpAction.execute();
        System.out.println("The card id query successful.");
        Context context = ActionContext.getActionContext().getContext();
        System.out.println("The name is " + context.getName() + " and cardId is " + context.getCardId());
    }
}

ActionContext聚合ThreadLocal

package com.dwz.concurrency2.chapter12;

public class ActionContext {
    
    private static final ThreadLocal<Context> threadlocal = new ThreadLocal<Context>() {
        @Override
        protected Context initialValue() {
            return new Context();
        };
    };
    
    private static class ContextHolder {
        private static final ActionContext actioncontext = new ActionContext();
    }
    
    public static ActionContext getActionContext() {
        return ContextHolder.actioncontext;
    }
    
    public Context getContext() {
        return threadlocal.get();
    }
}

Context

package com.dwz.concurrency2.chapter12;

public class Context {
    private String name;
    private String cardId;
    
    public void setName(String name) {
        this.name = name;
    }
    
    public String getName() {
        return this.name;
    }

    public void setCardId(String cardId) {
        this.cardId = cardId;
    }

    public String getCardId() {
        return cardId;
    }
}

QueryFromDBAction

package com.dwz.concurrency2.chapter12;

public class QueryFromDBAction {
    
    public void execute() {
        try {
            Thread.sleep(1000L);
            String name = "Alex " + Thread.currentThread().getName();
            ActionContext.getActionContext().getContext().setName(name);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

QueryFromHttpAction

package com.dwz.concurrency2.chapter12;

public class QueryFromHttpAction {
    
    public void execute() {
        Context context = ActionContext.getActionContext().getContext();
        String name = context.getName();
        String cardId = getCardId(name);
        context.setCardId(cardId);
    }
    
    private String getCardId(String name) {
        try {
            Thread.sleep(1000L);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "4464643@@" + Thread.currentThread().getId();
    }
}

测试

package com.dwz.concurrency2.chapter12;

import java.util.stream.IntStream;

public class ContextTest {
    public static void main(String[] args) {
        IntStream.range(1, 5).forEach(i -> new Thread(new ExecutionTask()).start());
    }
}