okhttp 默认使用 https 链接服务器，如果使用 http 会抛出现上面的异常

		
if (!Platform.get().isCleartextTrafficPermitted(host)) {
      throw new RouteException(new UnknownServiceException(
          "CLEARTEXT communication to " + host + " not permitted by network security policy"));
}		
		
		

创建文件 res/xml/network_security_config.xml 内容如下

		
neo@MacBook-Pro ~/AndroidStudioProjects/okhttp % cat app/src/main/res/xml/network_security_config.xml 
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true" />
</network-security-config>	
		
		

再 app/src/main/AndroidManifest.xml 文件中增加 android:networkSecurityConfig="@xml/network_security_config"

		
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.netkiller.okhttp">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:networkSecurityConfig="@xml/network_security_config">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

    <uses-permission android:name="android.permission.INTERNET" />
</manifest>