3.0 代码改为 jdk 1.8

mybatis-plus-annotation/build.gradle

@@ -1,6 +1,6 @@
 apply plugin: 'java'
 
-sourceCompatibility = 1.7
+sourceCompatibility = 1.8
 
 dependencies {
     testCompile 'junit:junit:4.12'

mybatis-plus-core/build.gradle

@@ -1,6 +1,6 @@
 apply plugin: 'java'
 
-sourceCompatibility = 1.7
+sourceCompatibility = 1.8
 
 dependencies {
     compile project(":mybatis-plus-annotation")

mybatis-plus-extension/build.gradle

@@ -1,6 +1,6 @@
 apply plugin: 'java'
 
-sourceCompatibility = 1.7
+sourceCompatibility = 1.8
 
 dependencies {
     compile project(":mybatis-plus-core")