java连接mysql，插入语句，不知道那里错了，求查出万分感谢

Question

package JDBCTest;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class TestOperation { Connection con; Statement stmt; ResultSet rs; //可能有问题 private String m_JDBCDrive="com.mysql.jdbc.Driver"; private String m_JDBCConnectionURL="jdbc:mysql://127.0.0.1:3306/xsxx"; private String m_userID="root"; private String m_password="1234"; public TestOperation(){ try { Class.forName(m_JDBCDrive).newInstance(); System.out.println("装载驱动成功"); } catch (InstantiationException e) { System.out.println("装载驱动失败"); } catch (IllegalAccessException e) { System.out.println("装载驱动失败"); } catch (ClassNotFoundException e) { System.out.println("装载驱动失败"); } } public boolean connect(){ try { con=DriverManager.getConnection(m_JDBCConnectionURL,m_userID,m_password); System.out.println("数据库连接正确"); } catch (SQLException e) { System.out.println("数据库连接失败"); return false; } return true; } public ResultSet getResult(String strSQL){ try { rs=stmt.executeQuery(strSQL); return rs; } catch (SQLException e) { System.out.println("执行SQL失败"); return null; } } public boolean updateSql(String strSQL){ try { stmt.executeUpdate(strSQL); con.commit(); return true; } catch (SQLException e) { System.out.println("执行SQL语句错误"); return false; } } public boolean insertSql(String strSQL){ try { stmt.executeUpdate(strSQL); con.commit(); return true; } catch (SQLException sqle) { System.out.println("insertSql():执行SQL语句错误"); return false; }} public void disconnect(){ try { if(con!=null){ con.close(); con=null; } } catch (SQLException e) { System.out.println("关闭数据库失败"); } } public static void main(String[] args) { TestOperation test=new TestOperation(); String sql1="insert into student(user,password,ID)  values('1002','admin2','admin2')"; String sql2; ResultSet rs; if(test.connect()){ if(test.insertSql(sql1)){ System.out.println("插入成功"); sql2="select * from student"; if(test.getResult(sql2)!=null){ rs=test.getResult(sql2); try{ while(rs.next()){ System.out.println(rs.getInt(1)); } }catch(SQLException e){ e.printStackTrace(); } } } test.disconnect(); } }

Answer 1

添加代码如下：
stmt=con.createStatement();

Answer 2

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Answer 3

弄个断点找找

Answer 4

Statement 没有初始化