android上最多有多少个http连接？

1.使用HttpUrlConnection能有几个

　　测试机器版本是5.1.1

个数	网络连接是否报错	写文件是否报错
1024	A/art: art/runtime/indirect_reference_table.cc:77] Check failed: table_mem_map_.get() != nullptr ashmem_create_region failed for 'indirect ref table': Too many open files	Check failed: table_mem_map_.get() != nullptr ashmem_create_region failed for 'indirect ref table': Too many open files
512	A/art: art/runtime/indirect_reference_table.cc:77] Check failed: table_mem_map_.get() != nullptr ashmem_create_region failed for 'indirect ref table': Too many open files	E/NativeCrypto: AppData::create pipe(2) failed: Too many open files
360	看网络环境，有时报错	E/NativeCrypto: AppData::create pipe(2) failed: Too many open files
256	ok	ok

2.使用okhttp有几个

同一个 url最大 5个连接
一个client最多64个网络连接

3.使用volley有几个

　　在RequestQueue.java中 

    /**
     * The set of all requests currently being processed by this RequestQueue. A Request
     * will be in this set if it is waiting in any queue or currently being processed by
     * any dispatcher.
     */
    private final Set<Request<?>> mCurrentRequests = new HashSet<Request<?>>();

　　用的HashSet,在它的构造函数注释中有:默认容量是16,装载因子是0.75.

    /**
     * Constructs a new, empty set; the backing <tt>HashMap</tt> instance has
     * default initial capacity (16) and load factor (0.75).
     */
    public HashSet() {
        map = new HashMap<>();
    }