Update Class::MybatisSetting

Author: Yanglin

META-INF/plugin.xml

@@ -1,7 +1,7 @@
 <idea-plugin version="2" url="https://github.com/seventh7/intellij-mybatis-plugin">
     <id>com.seventh7.plugin.mybatis</id>
     <name>MyBatis plugin</name>
-    <version>2.2</version>
+    <version>2.21</version>
     <vendor email="insist.day@gmail.com" url="https://github.com/seventh7">Yanglin</vendor>
 
     <description><![CDATA[
@@ -10,7 +10,7 @@
       ]]></description>
 
     <change-notes><![CDATA[
-      <h4>2.2</h4>
+      <h4>2.21</h4>
       <ul>
           <li>Rebuild mapper model</li>
           <li>Support more completion popup</li>

src/com/seventh7/mybatis/setting/MybatisSetting.java

@@ -53,10 +53,17 @@ public Element getState() {
     element.setAttribute(UPDATE_GENERATOR.getId(), gson.toJson(UPDATE_GENERATOR.getPatterns()));
     element.setAttribute(SELECT_GENERATOR.getId(), gson.toJson(SELECT_GENERATOR.getPatterns()));
     element.setAttribute(STATEMENT_GENERATE_MODEL_SETTING_ID, String.valueOf(statementGenerateModel.getIdentifier()));
+    setDefaultDataSourceIdIfNull();
     element.setAttribute(DEFAULT_SOURCE_SETTING_ID, defaultDataSourceId);
     return element;
   }
 
+  private void setDefaultDataSourceIdIfNull() {
+    if (this.defaultDataSourceId == null) {
+      this.defaultDataSourceId = "";
+    }
+  }
+
   @Override
   public void loadState(Element state) {
     loadState(state, INSERT_GENERATOR);
@@ -66,6 +73,7 @@ public void loadState(Element state) {
     final String model = state.getAttributeValue(STATEMENT_GENERATE_MODEL_SETTING_ID);
     statementGenerateModel = GenerateModel.getInstance(model);
     this.defaultDataSourceId = state.getAttributeValue(DEFAULT_SOURCE_SETTING_ID);
+    setDefaultDataSourceIdIfNull();
   }
 
   public String getDefaultDataSourceId() {