Detailed explanation of the operation example of resutset interface in JDBC

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  //1. next method, move down and determine whether there is any content  //2. getXXX method, obtain the content of the column based on the column index or column namepublic class Demo {
  @Test
  public void fun1() throws Exception{
    //1 Register driver    ("");
    //2 Get the connection    Connection conn = ("jdbc:mysql://localhost:3306/day05", "root", "1234");
    //3 Create Statement    Statement st = ();
    //4 Writing sql    String sql = "select * from t_user" ;
    //5 Execute sql    ResultSet rs = (sql);
    //Move one line down and judge    while(()){
      //There is data      //Get data: getXXX      int id = (1);//Get the value of the first column      //int id ("id");// Get the value of the id column      String name = (2);//Get the value of the second column      int age = (3);//Get the value of the third column      (id+"==>"+name+"==>"+age);
      
      //(columnIndex)
    }
    //6 Close the resource   ();
   ();
  }
  /* Database type java type
     int int
     double double
     decimal double
     char String
     varchar String
     datetime Date
     timestamp Timestamp/Date
    */
}

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public class Demo2 {
  @Test
  public void fun1() throws Exception{
    //1 Register driver    ("");
    //2 Get the connection    Connection conn = ("jdbc:mysql://localhost:3306/day05", "root", "1234");
    //3 Create Statement    Statement st = ();
    //4 Writing sql    String sql = "select * from t_user" ;
    //5 Execute sql    ResultSet rs = (sql);
    //Travel backwards      //1> After the cursor moves to the last line      ();
      //2> traversal=>      while(()){//Move the cursor upward and determine whether there is data        int id = ("id");// Get the value of the id column        String name = ("name");//Get the value of the second column        int age = ("age");//Get the value of the third column        (id+"==>"+name+"==>"+age);
      }
    //6 Close the resource   ();
   ();
  }
  /* Database type java type
     int int
     double double
     decimal double
     char String
     varchar String
     datetime Date
     timestamp Timestamp/Date
    */
}

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//ResultSet details// 2. Reversely modify the databasepublic class Demo3 {
  @Test
  public void fun1() throws Exception{
    //1 Register driver    ("");
    //2 Get the connection    Connection conn = ("jdbc:mysql://localhost:3306/day05", "root", "1234");
    //3 Create Statement    Statement st = (ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
    //4 Writing sql    String sql = "select * from t_user" ;
    //5 Execute sql    ResultSet rs = (sql);
    //Use the result set to reversely modify the database    ();//Move the cursor to the first line    ("name", "Tom");// Modify the value of the first row name column to Chinese Tom    ();// Confirm the modification    //6 Close the resource   ();
   ();
  }
}