MySQL execute、executeUpdate、executeQuery三者的区别

public static void main(String[] args) { 
 
 Connection conn = null; 
 Statement stm = null; 
 ResultSet rs = null; 
 try { 
  Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); 
  conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=Test;user=sa;password=sasa"); 
  stm = conn.createStatement(); 
  boolean ret = stm.execute("select * from stuinfo"); 
  if(ret){ 
  rs = stm.getResultSet(); 
  while(rs.next()){ 
   System.out.println("姓名："+rs.getString("stuName")+"\t年龄："+rs.getString("stuScore")); 
  } 
  } 
  ret = stm.execute("update stuinfo set stuScore=62 where stuname='张三'"); 
  int count = stm.getUpdateCount(); 
  if(!ret){ 
  System.out.println(count+"条数据修改成功！"); 
  } 
 } catch (ClassNotFoundException e) { 
  e.printStackTrace(); 
 } catch (SQLException e) { 
  e.printStackTrace(); 
 }  
 }