11_9-10:23

MyHomeWork/app/build.gradle

@@ -37,6 +37,9 @@ dependencies {
     implementation 'com.squareup.okhttp3:okhttp:4.4.0'
     implementation 'de.hdodenhof:circleimageview:3.1.0'
     //圆角图片
+    implementation files('libs/mysql-connector-java-8.0.27.jar')
+
+
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation 'com.google.android.material:material:1.3.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
@@ -46,6 +49,7 @@ dependencies {
     implementation 'androidx.navigation:navigation-ui:2.3.5'
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     implementation 'androidx.annotation:annotation:1.2.0'
+    implementation files('libs/mysql-connector-java-8.0.27.jar')
     testImplementation 'junit:junit:4.+'
     androidTestImplementation 'androidx.test.ext:junit:1.1.2'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

MyHomeWork/app/src/main/java/com/example/myhomework/Activity/MainActivity.java

@@ -51,7 +51,7 @@ public class MainActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
         binding = ActivityMainBinding.inflate(getLayoutInflater());
         setContentView(binding.getRoot());
-        InitUserDataUtil.ResetUserData(binding.getRoot(),this);
+        //InitUserDataUtil.ResetUserData(binding.getRoot(),this);
 
         BottomNavigationView navView = binding.navView;
         drawerLayout=binding.drawerLayout;

MyHomeWork/app/src/main/java/com/example/myhomework/Util/InitUserDataUtil.java

@@ -26,22 +26,22 @@ import java.util.Stack;
 
 
 public class InitUserDataUtil {
-    private static InitUserDataUtil initUserDataUtil=new InitUserDataUtil();
+    public static InitUserDataUtil initUserDataUtil=new InitUserDataUtil();
     private static String uid;
     private static String userNickName;
     private static UserType userType;
-    private static void InitUserDataUtil() {
+    private InitUserDataUtil() {
     }
-    public static InitUserDataUtil GetInitUserDataUtil(){
-
+    private static InitUserDataUtil GetInitUserDataUtil(){
         return initUserDataUtil;
     }
     public static void ResetUserData(View view,Activity activity){
+        /*
         NodeList list=null;
         FileInputStream fileInputStream=null;
-        /*
-        test to save userdata
-        */
+        //
+        //test to save userdata
+        //
         String str="<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n" +
                 "<userlist>\n" +
                 "    <user>\n" +
@@ -51,9 +51,9 @@ public class InitUserDataUtil {
                 "    </user>\n" +
                 "</userlist>";
         temp_save(str,activity);
-        /*
-        test to save userdata
-        */
+        //
+        //test to save userdata
+        //
         try {
             fileInputStream=activity.openFileInput("data.xml");
             list=ReadXmlUtil.GetdNodeLise(fileInputStream,"user" );
@@ -89,7 +89,8 @@ public class InitUserDataUtil {
                     }
                 }
             }
-        }
+        }*/
+
         Toast.makeText(view.getContext(),"uid:"+uid,Toast.LENGTH_LONG).show();
         Toast.makeText(view.getContext(),"userNickName:"+userNickName,Toast.LENGTH_LONG).show();
         Toast.makeText(view.getContext(),"userType:"+userType,Toast.LENGTH_LONG).show();
@@ -104,6 +105,7 @@ public class InitUserDataUtil {
         return userType.typeStr;
     }
     private void SetHead(){ }
+
     private static void temp_save(String str,Activity activity){
         FileOutputStream out=null;
         BufferedWriter writer=null;
@@ -123,30 +125,6 @@ public class InitUserDataUtil {
             }
         }
     }
-    private static String load(Activity activity){
-        FileInputStream in=null;
-        BufferedReader reader=null;
-        StringBuffer content=new StringBuffer();
-        try{
-            in=activity.openFileInput("data.xml");
-            reader=new BufferedReader(new InputStreamReader(in));
-            String line="";
-            while((line=reader.readLine())!=null){
-                content.append(line);
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        }finally {
-            if(reader!=null){
-                try{
-                    reader.close();
-                }catch (IOException e){
-                    e.printStackTrace();
-                }
-            }
-        }
-        return content.toString();
-    }
     protected enum UserType{
         Normal("普通用户",1),Admin("管理员",2);
         private String typeStr;

MyHomeWork/app/src/main/java/com/example/myhomework/Util/JDBCUtil.java

+package com.example.myhomework.Util;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public class JDBCUtil {
+    public static JDBCUtil jdbcUtil=new JDBCUtil();
+    public static Connection connection;
+    private JDBCUtil(){
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        super.finalize();
+        closeAll();
+    }
+
+    private void Connection() {
+        Connection connection = null;
+        try {
+            String SDdriver = "com.mysql.jdbc.Driver";
+            String SDurl = "jdbc:mysql://localhost:3306/emsdb?characterEncoding=utf8&useSSL=true";
+            //emsdb替换成自己的数据库名称
+            String SDuser = "root";
+            String SDpassword = "123456";
+            Class.forName(SDdriver);
+            connection = DriverManager.getConnection(SDurl, SDuser, SDpassword);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        PreparedStatement preparedStatement = null;
+        ResultSet resultSet = null;
+        String ss = new String("SELECT * from employer;");
+        try {
+            preparedStatement = connection.prepareStatement(ss);
+            resultSet = preparedStatement.executeQuery();
+            while (resultSet.next()) {
+                System.out.println(resultSet.getString("ename"));
+            }
+        } catch (SQLException ex) {
+        } finally {
+            closeAll(connection, preparedStatement, resultSet);
+        }
+    }
+
+    public static void closeAll(Connection connection, PreparedStatement preparedStatement,ResultSet resultSet) {
+        try {
+    //按顺序关闭
+            if(resultSet!=null) {
+                resultSet.close();
+            }
+            if (preparedStatement!=null) {
+                preparedStatement.close();
+            }
+            if (connection != null) {
+                connection.close();
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+}