非JPA，UsersDao实现

src/main/java/com/example/springdemo/dao/InterfaceDao/AbstractDao.java

@@ -0,0 +1,16 @@
+package com.example.springdemo.dao.InterfaceDao;
+
+import java.util.List;
+
+public interface AbstractDao<T> {
+
+    int insert(T t); //增
+
+    int delete(T t);//删
+
+    int update(T t);//改
+
+    List<T> search(T t);//查
+
+    T searchID(Long id);//查 ByID
+}

src/main/java/com/example/springdemo/dao/InterfaceDao/UsersDao.java

@@ -0,0 +1,7 @@
+package com.example.springdemo.dao.InterfaceDao;
+
+import com.example.springdemo.dao.InterfaceDao.AbstractDao;
+import com.example.springdemo.entities.Users;
+
+public interface UsersDao extends AbstractDao<Users> {
+}

src/main/java/com/example/springdemo/dao/impl/CommonDao.java

@@ -0,0 +1,28 @@
+package com.example.springdemo.dao.impl;
+
+import com.example.springdemo.utils.DataBaseUtil;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public class CommonDao<T> {
+    DataBaseUtil dataBaseUtil = new DataBaseUtil();
+    public int delete(Connection ct, PreparedStatement ps, ResultSet rs,
+                             String sql, Long id) {
+
+        int flag;
+        try {
+            ct = dataBaseUtil.getConnection();
+            ps = ct.prepareStatement(sql);
+            ps.setLong(1, id);
+            flag = ps.executeUpdate();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        } finally {
+            dataBaseUtil.close(ct, ps, rs);
+        }
+        return flag;
+    }
+}

src/main/java/com/example/springdemo/dao/impl/UsersDaoImpl.java

@@ -0,0 +1,132 @@
+package com.example.springdemo.dao.impl;
+
+import com.example.springdemo.dao.InterfaceDao.UsersDao;
+import com.example.springdemo.entities.Users;
+import com.example.springdemo.utils.DataBaseUtil;
+import org.jetbrains.annotations.NotNull;
+import org.springframework.stereotype.Component;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+public class UsersDaoImpl implements UsersDao {
+    private Connection connection = null;
+    private PreparedStatement preparedStatement = null;
+    private ResultSet resultSet = null;
+    DataBaseUtil dataBaseUtil = new DataBaseUtil();
+    //新建用户
+    @Override
+    public int insert(@NotNull Users users) {
+        int flag;
+        try {
+            connection = dataBaseUtil.getConnection();
+            String insert_sql = "insert into Users(name, phoneNumber, address, password) " + "values (?,?,?,?)";
+            preparedStatement = connection.prepareStatement(insert_sql);
+
+            preparedStatement.setString(1, users.getName());
+            preparedStatement.setString(2, users.getPhoneNumber());
+            preparedStatement.setString(3, users.getAddress());
+            preparedStatement.setString(4, users.getPassword());
+
+            flag = preparedStatement.executeUpdate();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        } finally {
+            dataBaseUtil.close(connection, preparedStatement, resultSet);
+        }
+        return flag;
+    }
+
+    //删除
+    @Override
+    public int delete(@NotNull Users user) {
+        String delete_sql = "delete from Users where id=?";
+        CommonDao<Users> dao = new CommonDao<>();
+        return  dao.delete(connection, preparedStatement, resultSet,
+                        delete_sql, user.getId());
+    }
+
+    //更新用户个人信息
+    //@TODO 只能更新所有信息，不能选择性更新
+    @Override
+    public int update(@NotNull Users users) {
+        int flag;
+        String update_sql = "update Users " + "set name = ?, phoneNumber = ?, address = ? " + "where id = ?";
+
+        try {
+            connection = dataBaseUtil.getConnection();
+            preparedStatement = connection.prepareStatement(update_sql);
+
+            preparedStatement.setString(1, users.getName());
+            preparedStatement.setString(2, users.getPhoneNumber());
+            preparedStatement.setString(3, users.getAddress());
+            preparedStatement.setLong(4, users.getId());
+
+            flag = preparedStatement.executeUpdate();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        return flag;
+    }
+
+    //查询所有用户
+    @Override
+    public @NotNull List<Users> search(@NotNull Users user) {
+        List<Users> list = new ArrayList<>();
+        String selectAll_sql = "select * from Users";
+
+        try {
+            connection = dataBaseUtil.getConnection();
+
+            preparedStatement = connection.prepareStatement(selectAll_sql);
+            resultSet = preparedStatement.executeQuery();
+
+            while (resultSet.next()) {
+                user = new Users();
+                SetAttribute(user, resultSet);
+                list.add(user);
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        } finally {
+            dataBaseUtil.close(connection, preparedStatement, resultSet);
+        }
+        return list;
+    }
+
+    //用ID查询用户
+    @Override
+    public @NotNull Users searchID(@NotNull Long id) {
+        Users user = null;
+        String selectID_sql = "select * from Users where id = ?";
+        try {
+            connection = dataBaseUtil.getConnection();
+            preparedStatement = connection.prepareStatement(selectID_sql);
+            preparedStatement.setLong(1, id);
+            resultSet = preparedStatement.executeQuery();
+
+            while (resultSet.next()) {
+                user = new Users();
+                SetAttribute(user, resultSet);
+            }
+
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        } finally {
+            dataBaseUtil.close(connection, preparedStatement, resultSet);
+        }
+
+        return user;
+    }
+    private void SetAttribute(@NotNull Users user, @NotNull ResultSet rs) throws SQLException {
+        user.setId(rs.getLong("id"));
+        user.setName(rs.getString("name"));
+        user.setPhoneNumber(rs.getString("phoneNumber"));
+        user.setAddress(rs.getString("address"));
+    }
+}

src/main/java/com/example/springdemo/entities/Users.java

@@ -1,5 +1,9 @@
 package com.example.springdemo.entities;
 
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -10,9 +14,13 @@ import lombok.NoArgsConstructor;
 @Builder
 @NoArgsConstructor
 @AllArgsConstructor
+@Entity
+@Table(name = "Users")
 public class Users {
+    @Id
     private Long id;//主键，用户ID
     private String name;//用户姓名
+    @Column(name = "phoneNumber")
     private String phoneNumber;//用户联系方式
     private String address;//家庭住址
     private String password;//用户密码

src/main/java/com/example/springdemo/utils/DataBaseUtil.java

@@ -0,0 +1,48 @@
+package com.example.springdemo.utils;
+
+import com.example.springdemo.config.DataBaseProperties;
+import jakarta.annotation.Resource;
+import org.springframework.stereotype.Component;
+
+import java.sql.*;
+
+@Component
+public class DataBaseUtil {
+    @Resource
+    DataBaseProperties dataBaseProperties;
+    // Connect to database
+    private final String connectionUrl =
+            dataBaseProperties.getUrl() +
+                    dataBaseProperties.getUsername() +
+                    dataBaseProperties.getPassword();
+
+    public Connection getConnection() {
+        Connection connection = null;
+        try {
+            // Code here.
+            connection = DriverManager.getConnection(connectionUrl);
+        }
+        // Handle any errors that may have occurred.
+        catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return connection;
+    }
+
+    //释放资源
+    public void close(Connection conn, Statement st, ResultSet rs) {
+        try {
+            if (rs != null) {
+                rs.close();
+            }
+            if (st != null) {
+                st.close();
+            }
+            if (conn != null) {
+                conn.close();
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}