Android connects to MySQL database and explains the operation examples of adding deleting modifying and searching

1. Android connects to MySQL database

public class DBOpenHelper {
 
  private static String driver = "com.mysql.jdbc.Driver";//MySQL  Drive 
  private static String url = "jdbc:mysql://IP:3306/ Database ";//MYSQL Database connection Url
  private static String user = "root";// User name 
  private static String password = "root";// Password 
 
  /**
   *  Connect to a database 
   * */
 
  public static Connection getConn(){
    Connection conn = null;
    try {
      Class.forName(driver);// Get MYSQL Drive 
      conn = (Connection) DriverManager.getConnection(url, user, password);// Get a connection 
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    } catch (SQLException e) {
      e.printStackTrace();
    }
    return conn;
  }
 
  /**
   *  Close the database 
   * */
 
  public static void closeAll(Connection conn, PreparedStatement ps){
    if (conn != null) {
      try {
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    if (ps != null) {
      try {
        ps.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
 
  }
 
  /**
   *  Close the database 
   * */
 
  public static void closeAll(Connection conn, PreparedStatement ps, ResultSet rs){
    if (conn != null) {
      try {
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    if (ps != null) {
      try {
        ps.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    if (rs != null) {
      try {
        rs.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
  }
 
}

2. Add, delete and check

public class DBService {
 
  private Connection conn=null; // Open a database object 
  private PreparedStatement ps=null;// Operational integration sql Object of the statement 
  private ResultSet rs=null;// Collection of query results 
 
  //DBService  Object 
  public static DBService dbService=null;
 
  /**
   *  Construction method   Privatization 
   * */
 
  private DBService(){
 
  }
 
  /**
   *  Get MySQL Database singleton class object 
   * */
 
  public static DBService getDbService(){
    if(dbService==null){
      dbService=new DBService();
    }
    return dbService;
  }
 
 
  /**
   *  Get the patient information to send SMS    Check 
   * */
 
  public List<User> getUserData(){
    // Result storage collection 
    List<User> list=new ArrayList<User>();
    //MySQL  Statement 
    String sql="select * from user";
    // Getting Linked Database Objects 
    conn= DBOpenHelper.getConn();
    try {
      if(conn!=null&&(!conn.isClosed())){
        ps= (PreparedStatement) conn.prepareStatement(sql);
        if(ps!=null){
          rs= ps.executeQuery();
          if(rs!=null){
            while(rs.next()){
              User u=new User();
              u.setId(rs.getString("id"));
              u.setName(rs.getString("name"));
              u.setPhone(rs.getString("phone"));
              u.setContent(rs.getString("content"));
              u.setState(rs.getString("state"));
              list.add(u);
            }
          }
        }
      }
    } catch (SQLException e) {
      e.printStackTrace();
    }
    DBOpenHelper.closeAll(conn,ps,rs);// Close related operations 
    return list;
  }
 
  /**
   *  Modify the state of an object in the database    Change 
   * */
 
  public int updateUserData(String phone){
    int result=-1;
    if(!StringUtils.isEmpty(phone)){
      // Getting Linked Database Objects 
      conn= DBOpenHelper.getConn();
      //MySQL  Statement 
      String sql="update user set state=? where phone=?";
      try {
        boolean closed=conn.isClosed();
        if(conn!=null&&(!closed)){
          ps= (PreparedStatement) conn.prepareStatement(sql);
          ps.setString(1,"1");// No. 1 1 Parameters state 1 It must be with the above SQL Statement field order 1 To 
          ps.setString(2,phone);// No. 1 2 Parameters  phone 1 It must be with the above SQL Statement field order 1 To 
          result=ps.executeUpdate();// Return 1  Successful execution 
        }
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    DBOpenHelper.closeAll(conn,ps);// Close related operations 
    return result;
  }
 
  /**
   *  Insert data into the database in batches    Increase 
   * */
 
  public int insertUserData(List<User> list){
    int result=-1;
    if((list!=null)&&(list.size()>0)){
      // Getting Linked Database Objects 
      conn= DBOpenHelper.getConn();
      //MySQL  Statement 
      String sql="INSERT INTO user (name,phone,content,state) VALUES (?,?,?,?)";
      try {
        boolean closed=conn.isClosed();
        if((conn!=null)&&(!closed)){
          for(User user:list){
            ps= (PreparedStatement) conn.prepareStatement(sql);
            String name=user.getName();
            String phone=user.getPhone();
            String content=user.getContent();
            String state=user.getState();
            ps.setString(1,name);// No. 1 1 Parameters  name  Same rules as above 
            ps.setString(2,phone);// No. 1 2 Parameters  phone  Same rules as above 
            ps.setString(3,content);// No. 1 3 Parameters  content  Same rules as above 
            ps.setString(4,state);// No. 1 4 Parameters  state  Same rules as above 
            result=ps.executeUpdate();// Return 1  Successful execution 
          }
        }
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    DBOpenHelper.closeAll(conn,ps);// Close related operations 
    return result;
  }
 
  
  /**
   *  Delete data   Delete 
   * */
 
  public int delUserData(String phone){
    int result=-1;
    if((!StringUtils.isEmpty(phone))&&(PhoneNumberUtils.isMobileNumber(phone))){
      // Getting Linked Database Objects 
      conn= DBOpenHelper.getConn();
      //MySQL  Statement 
      String sql="delete from user where phone=?";
      try {
        boolean closed=conn.isClosed();
        if((conn!=null)&&(!closed)){
          ps= (PreparedStatement) conn.prepareStatement(sql);
          ps.setString(1, phone);
          result=ps.executeUpdate();// Return 1  Successful execution 
        }
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    DBOpenHelper.closeAll(conn,ps);// Close related operations 
    return result;
  }
 
}