Merge pull request alibaba#712 from paderlol/develop

When using open jdk to log in to nacos it failed.   alibaba#711

distribution/bin/startup.sh

@@ -13,16 +13,43 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+cygwin=false
+darwin=false
+os400=false
+case "`uname`" in
+CYGWIN*) cygwin=true;;
+Darwin*) darwin=true;;
+OS400*) os400=true;;
+esac
 error_exit ()
 {
     echo "ERROR: $1 !!"
     exit 1
 }
-
 [ ! -e "$JAVA_HOME/bin/java" ] && JAVA_HOME=$HOME/jdk/java
 [ ! -e "$JAVA_HOME/bin/java" ] && JAVA_HOME=/usr/java
 [ ! -e "$JAVA_HOME/bin/java" ] && JAVA_HOME=/opt/taobao/java
-[ ! -e "$JAVA_HOME/bin/java" ] && error_exit "Please set the JAVA_HOME variable in your environment, We need java(x64)! jdk8 or later is better!"
+[ ! -e "$JAVA_HOME/bin/java" ] && unset JAVA_HOME
+
+if [ -z "$JAVA_HOME" ]; then
+  if $darwin; then
+
+    if [ -x '/usr/libexec/java_home' ] ; then
+      export JAVA_HOME=`/usr/libexec/java_home`
+
+    elif [ -d "/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home" ]; then
+      export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home"
+    fi
+  else
+    JAVA_PATH=`dirname $(readlink -f $(which javac))`
+    if [ "x$JAVA_PATH" != "x" ]; then
+      export JAVA_HOME=`dirname $JAVA_PATH 2>/dev/null`
+    fi
+  fi
+  if [ -z "$JAVA_HOME" ]; then
+        error_exit "Please set the JAVA_HOME variable in your environment, We need java(x64)! jdk8 or later is better!"
+  fi
+fi
 
 export MODE="cluster"
 while getopts ":m:" opt