利用Apache Common将java对象池化的问题

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
            <version>2.9.0</version>
        </dependency>

public class Foo {
    private final String username;
    public Foo(String username) {
        this.username = username;
    }
    public String getUsername() {
        return username;
    }
}

public class FooPoolObjectFactory extends BasePooledObjectFactory<Foo> {
    @Override
    public Foo create() throws Exception {
        return new Foo(String.valueOf(RandomUtils.randomInt(0, 10)));
    }
    @Override
    public PooledObject<Foo> wrap(Foo obj) {
        return new DefaultPooledObject<>(obj);
    }
}

public class FooEvictionPolicy implements EvictionPolicy<Foo> {
    @Override
    public boolean evict(EvictionConfig config, PooledObject<Foo> underTest, int idleCount) {
        // todo  定期检查对象某些功能是否可用
        return true;
    }
}

    public GenericObjectPool<Foo> fooGenericObjectPool() {
        GenericObjectPoolConfig<Foo> poolConfig = new GenericObjectPoolConfig<>();
        poolConfig.setEvictionPolicy(new FooEvictionPolicy());
        poolConfig.setBlockWhenExhausted(true);
        poolConfig.setJmxEnabled(false);
        poolConfig.setMaxWaitMillis(1000 * 10);
        poolConfig.setTimeBetweenEvictionRunsMillis(60 * 1000);
        poolConfig.setMinEvictableIdleTimeMillis(20 * 1000);
        poolConfig.setTestWhileIdle(true);
        poolConfig.setTestOnReturn(true);
        poolConfig.setTestOnBorrow(true);
        poolConfig.setMaxTotal(3);
        // 设置抛弃策略
        AbandonedConfig abandonedConfig = new AbandonedConfig();
        abandonedConfig.setRemoveAbandonedOnMaintenance(true);
        abandonedConfig.setRemoveAbandonedOnBorrow(true);
        return new GenericObjectPool<>(new FooPoolObjectFactory(), poolConfig, abandonedConfig);
    }

    private final GenericObjectPool<Foo> fooGenericObjectPool = fooGenericObjectPool();
    public Foo borrowFoo () throws Exception {
        return fooGenericObjectPool.borrowObject();
    }
    public void returnObject(Foo foo){
        fooGenericObjectPool.returnObject(foo);
    }