想要设置以太网为静态IP通过搜索是需用到EthernetManager，但是EthernetManager是谷歌隐藏的API，app是无法调用到的，所以只能通过反射来进行设置

也可以通过下载系统的class.jar包，放到自己的项目中，就可以不用反射，直接调用

下边是引入jar包直接调用的代码，通过EthernetManager 的setConfiguration方法来设置，但是需要构造IpConfiguration 和StaticIpConfiguration对象，IpConfiguration.IpAssignment.STATIC就代表设置为静态IP，也可以设置DHCP

private void setStaticIP() {
        EthernetManager mEthManager = (EthernetManager) getSystemService("ethernet");
        StaticIpConfiguration mStaticIpConfiguration = new StaticIpConfiguration();
        /*
         * get ip address, netmask,dns ,gw etc.
         */
        Inet4Address inetAddr = getIPv4Address(mEthIpAddress);
        int prefixLength = NetUtils.maskStr2InetMask(mEthNetmask);
        InetAddress gatewayAddr = getIPv4Address(mEthGateway);
        InetAddress dnsAddr = getIPv4Address(mEthdns1);

        if (inetAddr.getAddress().toString().isEmpty() || prefixLength ==0 || gatewayAddr.toString().isEmpty()
                || dnsAddr.toString().isEmpty()) {
           return;
        }

        Class<?> clazz = null;
        try {
            clazz = Class.forName("android.net.LinkAddress");
        } catch (Exception e) {
            // TODO: handle exception
        }

        Class[] cl = new Class[]{InetAddress.class, int.class};
        Constructor cons = null;

        //取得所有构造函数
        try {
             cons = clazz.getConstructor(cl);
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }

        //给传入参数赋初值
        Object[] x = {inetAddr, prefixLength};

        String dnsStr2 = mEthdns2;
        //mStaticIpConfiguration.ipAddress = new LinkAddress(inetAddr, prefixLength);
        try {
            mStaticIpConfiguration.ipAddress = (LinkAddress) cons.newInstance(x);
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        mStaticIpConfiguration.gateway=gatewayAddr;
        mStaticIpConfiguration.dnsServers.add(dnsAddr);

        if (!dnsStr2.isEmpty()) {
            mStaticIpConfiguration.dnsServers.add(getIPv4Address(dnsStr2));
        }

        Log.d("2312321", "chanson mStaticIpConfiguration  ====" + mStaticIpConfiguration);

        IpConfiguration mIpConfiguration = new IpConfiguration(IpConfiguration.IpAssignment.STATIC, IpConfiguration.ProxySettings.NONE, mStaticIpConfiguration, null);

        mEthManager.setConfiguration(mIpConfiguration);
    }

参考项目链接

不想引用jar包的话就需要使用反射来实现，下边代码是我模仿这个逻辑通过反射来实现的代码

try {
    Class<?> ethernetManagerCls = Class.forName("android.net.EthernetManager");

    //获取EthernetManager实例
    Object ethManager = VfiServiceApp.getContext().getSystemService("ethernet");

    // get ip address, netmask,dns ,gw etc.
    Inet4Address inetAddr = getIPv4Address(STATIC_IP);
    int prefixLength = NetUtils.maskStr2InetMask(STATIC_NETMASK);
    InetAddress gatewayAddr = getIPv4Address(STATIC_GATEWAY);
    InetAddress dnsAddr = getIPv4Address(STATIC_DNS1);

    Class<?> clazz = Class.forName("android.net.LinkAddress");

    if (ethManager == null || inetAddr == null || inetAddr.getAddress() == null || gatewayAddr == null
            || dnsAddr == null || Arrays.toString(inetAddr.getAddress()).isEmpty() || prefixLength == 0
            || gatewayAddr.toString().isEmpty() || dnsAddr.toString().isEmpty() || clazz == null) {
        return;
    }

    Class[] cl = new Class[]{InetAddress.class, int.class};
    Constructor cons = null;

    //取得所有构造函数
    try {
        cons = clazz.getConstructor(cl);
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    }

    if (cons == null) {
        return;
    }
    //给传入参数赋初值
    Object[] x = {inetAddr, prefixLength};


    Class<?> staticIpConfigurationCls = Class.forName("android.net.StaticIpConfiguration");
    //实例化StaticIpConfiguration
    Object staticIpConfiguration = null;

    staticIpConfiguration = staticIpConfigurationCls.newInstance();
    Field ipAddress = staticIpConfigurationCls.getField("ipAddress");
    Field gateway = staticIpConfigurationCls.getField("gateway");
    Field dnsServers = staticIpConfigurationCls.getField("dnsServers");
    //设置ipAddress
    ipAddress.set(staticIpConfiguration, (LinkAddress) cons.newInstance(x));
    //设置网关
    gateway.set(staticIpConfiguration, gatewayAddr);
    //设置dns
    ArrayList<InetAddress> dnsList = (ArrayList<InetAddress>) dnsServers.get(staticIpConfiguration);
    dnsList.add(dnsAddr);
    if (!STATIC_DNS2.isEmpty()) {
        dnsList.add(getIPv4Address(STATIC_DNS2));
    }
    Log.d(TAG, "chanson mStaticIpConfiguration  ====" + staticIpConfigurationCls);

    Class<?> ipConfigurationCls = Class.forName("android.net.IpConfiguration");
    Object ipConfiguration = ipConfigurationCls.newInstance();
    //设置StaticIpConfiguration
    Field staticIpConfigurationField = ipConfigurationCls.getField("staticIpConfiguration");
    staticIpConfigurationField.set(ipConfiguration, staticIpConfiguration);
    //获取ipAssignment、proxySettings的枚举值
    Map<String, Object> ipConfigurationEnum = getIpConfigurationEnum(ipConfigurationCls);
    //设置ipAssignment
    Field ipAssignment = ipConfigurationCls.getField("ipAssignment");
    ipAssignment.set(ipConfiguration, ipConfigurationEnum.get("IpAssignment.STATIC"));
    //设置proxySettings
    Field proxySettings = ipConfigurationCls.getField("proxySettings");
    proxySettings.set(ipConfiguration, ipConfigurationEnum.get("ProxySettings.NONE"));

    @SuppressLint("PrivateApi")
    Method setConfigurationMethod = ethernetManagerCls.getDeclaredMethod("setConfiguration", ipConfiguration.getClass());
    //设置静态IP
    setConfigurationMethod.invoke(ethManager, ipConfiguration);
} catch (NoSuchFieldException | IllegalAccessException | InstantiationException | InvocationTargetException | ClassNotFoundException | NoSuchMethodException e) {
    e.printStackTrace();
}

最好放到主线程中执行，因为我之前测试在子线程有报错，所以需要切换到主线程，参考文章https://www.jianshu.com/p/16792c2ef112

两种方式都可以设置成功，根据个人需要使用即可，class.jar可以通过到参考项目libs中进行下载

当然还需要应用有系统权限才可以设置，所以需要改为系统应用并进行系统签名才可真正设置成功