diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index e4bad21..e9aa82d 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -2,7 +2,6 @@
 <project version="4">
   <component name="ChangeListManager">
     <list default="true" id="42982c84-cdb2-4596-b4aa-818c31fc199a" name="Default" comment="">
-      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/workspace.xml" afterPath="$PROJECT_DIR$/.idea/workspace.xml" />
       <change type="MODIFICATION" beforePath="$PROJECT_DIR$/src/main/java/security.java" afterPath="$PROJECT_DIR$/src/main/java/security.java" />
       <change type="MODIFICATION" beforePath="$PROJECT_DIR$/src/main/java/test.java" afterPath="$PROJECT_DIR$/src/main/java/test.java" />
     </list>
@@ -23,7 +22,9 @@
           <provider selected="true" editor-type-id="text-editor">
             <state relative-caret-position="289">
               <caret line="17" column="10" lean-forward="false" selection-start-line="17" selection-start-column="10" selection-end-line="17" selection-end-column="10" />
-              <folding />
+              <folding>
+                <marker date="1504604535000" expanded="true" signature="89:618" ph="..." />
+              </folding>
             </state>
           </provider>
         </entry>
@@ -44,8 +45,8 @@
       <file leaf-file-name="security.java" pinned="false" current-in-tab="true">
         <entry file="file://$PROJECT_DIR$/src/main/java/security.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="163">
-              <caret line="10" column="0" lean-forward="true" selection-start-line="10" selection-start-column="0" selection-end-line="10" selection-end-column="0" />
+            <state relative-caret-position="276">
+              <caret line="66" column="59" lean-forward="false" selection-start-line="66" selection-start-column="59" selection-end-line="66" selection-end-column="59" />
               <folding>
                 <element signature="n#!!doc" expanded="true" />
                 <element signature="imports" expanded="true" />
@@ -57,8 +58,8 @@
       <file leaf-file-name="test.java" pinned="false" current-in-tab="false">
         <entry file="file://$PROJECT_DIR$/src/main/java/test.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="238">
-              <caret line="14" column="0" lean-forward="true" selection-start-line="14" selection-start-column="0" selection-end-line="14" selection-end-column="0" />
+            <state relative-caret-position="289">
+              <caret line="17" column="50" lean-forward="false" selection-start-line="17" selection-start-column="50" selection-end-line="17" selection-end-column="50" />
               <folding />
             </state>
           </provider>
@@ -87,8 +88,8 @@
         <option value="$PROJECT_DIR$/pom.xml" />
         <option value="$PROJECT_DIR$/src/main/java/main.java" />
         <option value="$PROJECT_DIR$/README.md" />
-        <option value="$PROJECT_DIR$/src/main/java/security.java" />
         <option value="$PROJECT_DIR$/src/main/java/test.java" />
+        <option value="$PROJECT_DIR$/src/main/java/security.java" />
       </list>
     </option>
   </component>
@@ -99,8 +100,6 @@
     <sorting>DEFINITION_ORDER</sorting>
   </component>
   <component name="ProjectFrameBounds">
-    <option name="x" value="-1280" />
-    <option name="y" value="214" />
     <option name="width" value="1280" />
     <option name="height" value="800" />
   </component>
@@ -658,15 +657,15 @@
       <option name="number" value="Default" />
       <option name="presentableId" value="Default" />
       <updated>1504604417100</updated>
-      <workItem from="1504604422158" duration="2421000" />
+      <workItem from="1504604422158" duration="3470000" />
     </task>
     <servers />
   </component>
   <component name="TimeTrackingManager">
-    <option name="totallyTimeSpent" value="2421000" />
+    <option name="totallyTimeSpent" value="3470000" />
   </component>
   <component name="ToolWindowManager">
-    <frame x="-1280" y="214" width="1280" height="800" extended-state="6" />
+    <frame x="0" y="0" width="1280" height="800" extended-state="0" />
     <editor active="true" />
     <layout>
       <window_info id="Palette" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" show_stripe_button="true" weight="0.33" sideWeight="0.5" order="-1" side_tool="false" content_ui="tabs" />
@@ -750,7 +749,9 @@
       <provider selected="true" editor-type-id="text-editor">
         <state relative-caret-position="289">
           <caret line="17" column="10" lean-forward="false" selection-start-line="17" selection-start-column="10" selection-end-line="17" selection-end-column="10" />
-          <folding />
+          <folding>
+            <marker date="1504604535000" expanded="true" signature="89:618" ph="..." />
+          </folding>
         </state>
       </provider>
     </entry>
@@ -775,16 +776,16 @@
     </entry>
     <entry file="file://$PROJECT_DIR$/src/main/java/test.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="238">
-          <caret line="14" column="0" lean-forward="true" selection-start-line="14" selection-start-column="0" selection-end-line="14" selection-end-column="0" />
+        <state relative-caret-position="289">
+          <caret line="17" column="50" lean-forward="false" selection-start-line="17" selection-start-column="50" selection-end-line="17" selection-end-column="50" />
           <folding />
         </state>
       </provider>
     </entry>
     <entry file="file://$PROJECT_DIR$/src/main/java/security.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="163">
-          <caret line="10" column="0" lean-forward="true" selection-start-line="10" selection-start-column="0" selection-end-line="10" selection-end-column="0" />
+        <state relative-caret-position="276">
+          <caret line="66" column="59" lean-forward="false" selection-start-line="66" selection-start-column="59" selection-end-line="66" selection-end-column="59" />
           <folding>
             <element signature="n#!!doc" expanded="true" />
             <element signature="imports" expanded="true" />
diff --git a/src/main/java/security.java b/src/main/java/security.java
index 2c9f01b..dd0883d 100644
--- a/src/main/java/security.java
+++ b/src/main/java/security.java
@@ -4,6 +4,9 @@
  * Date: 2017.09.05
  */
 
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.InetAddress;
 import java.net.URL;
 import com.google.common.net.InternetDomainName;
 
@@ -13,7 +16,7 @@ public class security {
         * 检测传入的URL是否在白名单的域名里
         * url：需要检测的URL
         * urlWList: 一级域名的域名列表，比如String[] urlWList = {"joychou.com", "joychou.me"};
-        * 合法URL返回true，非法URL返回false
+        * 返回值：合法URL返回true，非法URL返回false
      */
     public static Boolean checkUrlWlist(String url, String[] urlWList) {
         try {
@@ -39,6 +42,125 @@ public class security {
         }
     }
 
+
+    /*
+        * 判断一个URL的IP是否是内网IP
+        * 如果是内网IP，返回true
+        * 非内网IP，返回false
+    */
+    public static boolean isInnerIpFromUrl(String url) throws Exception {
+        String domain = getUrlDomain(url);
+        if (domain.equals("")) {
+            return true; // 异常URL当成内网IP等非法URL处理
+        }
+
+        String ip = DomainToIP(domain);
+        if(ip.equals("")){
+            return true; // 如果域名转换为IP异常，则认为是非法URL
+        }
+        return isInnerIp(ip);
+    }
+
+
+    /*
+        * check SSRF (判断逻辑为判断URL的IP是否是内网IP)
+        * 如果是内网IP，返回false，表示checkSSRF不通过。否则返回true。即合法返回true
+        * URL只支持HTTP协议
+        * 设置了访问超时时间为3s
+     */
+    public static Boolean checkSSRF(String url) {
+
+        HttpURLConnection connection;
+        String finalUrl = url;
+        try {
+            do {
+                // 判断当前请求的URL是否是内网ip
+                Boolean bRet = isInnerIpFromUrl(finalUrl);
+                if (bRet) {
+                    return true;
+                }
+
+                connection = (HttpURLConnection) new URL(finalUrl).openConnection();
+                connection.setInstanceFollowRedirects(false);
+                connection.setUseCaches(false); // 设置为false，手动处理跳转，可以拿到每个跳转的URL
+                connection.setConnectTimeout(3*1000); // 设置连接超时时间为3s
+                //connection.setRequestMethod("GET");
+                connection.connect(); // 会解析dns
+                int responseCode = connection.getResponseCode(); // 发起网络请求
+                if (responseCode >= 300 && responseCode < 400) {
+                    String redirectedUrl = connection.getHeaderField("Location");
+                    if (null == redirectedUrl)
+                        break;
+                    finalUrl = redirectedUrl;
+                    System.out.println("redirected url: " + finalUrl);
+                } else
+                    break;
+            } while (connection.getResponseCode() != HttpURLConnection.HTTP_OK);
+            connection.disconnect();
+        } catch (Exception e) {
+            return false;
+        }
+        return false;
+    }
+
+    /*
+        内网IP：
+        10.0.0.1 - 10.255.255.254       (10.0.0.0/8)
+        192.168.0.1 - 192.168.255.254   (192.168.0.0/16)
+        127.0.0.1 - 127.255.255.254     (127.0.0.0/8)
+        172.16.0.1 - 172.31.255.254     (172.16.0.0/12)
+    */
+    public static boolean isInnerIp(String strIP) throws IOException {
+        try{
+            String[] ipArr = strIP.split("\\.");
+            if (ipArr.length != 4){
+                return false;
+            }
+
+            int ip_split1 = Integer.parseInt(ipArr[1]);
+
+            return (ipArr[0].equals("10") ||
+                    ipArr[0].equals("127") ||
+                    (ipArr[0].equals("172") && ip_split1 >= 16 && ip_split1 <=31) ||
+                    (ipArr[0].equals("192") && ipArr[1].equals("168")));
+        }catch (Exception e) {
+            return false;
+        }
+
+    }
+    /*
+        * 域名转换为IP
+        * 会将各种进制的ip转为正常ip
+        * 167772161转换为10.0.0.1
+        * 127.0.0.1.xip.io转换为127.0.0.1
+    */
+    public static String DomainToIP(String domain) throws IOException{
+        try {
+            InetAddress IpAddress = InetAddress.getByName(domain);
+            return IpAddress.getHostAddress();
+        }
+        catch (Exception e) {
+            return "";
+        }
+    }
+
+    /*
+        从URL中获取域名
+        限制为http/https协议
+    */
+    public static String getUrlDomain(String url) throws IOException{
+        try {
+            URL u = new URL(url);
+            if (!u.getProtocol().startsWith("http") && !u.getProtocol().startsWith("https")) {
+                throw new IOException("Protocol error: " + u.getProtocol());
+            }
+            return u.getHost();
+        } catch (Exception e) {
+            return "";
+        }
+
+    }
+
     public static void main(String[] args) throws Exception {
 
     }
diff --git a/src/main/java/test.java b/src/main/java/test.java
index 29a7462..ba0e090 100644
--- a/src/main/java/test.java
+++ b/src/main/java/test.java
@@ -6,9 +6,16 @@
 
 public class test {
     public static void main(String[] args) throws Exception {
+
+        // URL白名单组件测试
         security checkUrl = new security();
         String[] urlWList = {"joychou.com", "joychou.me"};
         Boolean ret = checkUrl.checkUrlWlist("http://test.joychou.me", urlWList);
         System.out.println(ret);
+
+        // SSRF组件测试
+
+        ret = checkUrl.checkSSRF("http://127.0.0.1");
+        System.out.println(ret);
     }
 }
diff --git a/target/classes/security.class b/target/classes/security.class
index 9555903..a43fc1d 100644
Binary files a/target/classes/security.class and b/target/classes/security.class differ
diff --git a/target/classes/test.class b/target/classes/test.class
index 0b91ace..2de076d 100644
Binary files a/target/classes/test.class and b/target/classes/test.class differ