Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- import java.sql.Connection;
- import java.sql.DriverManager;
- public class DBConnection {
- public static Connection getDBConnection() {
- String url = "jdbc:mysql://localhost:3306/";
- String dbName = "expenseCalc";
- String driver = "com.mysql.jdbc.Driver";
- String userName = "*********";
- String password = "*******";
- Connection conn = null;
- try {
- Class.forName(driver).newInstance();
- conn = (Connection) DriverManager.getConnection(url + dbName, userName, password);
- } catch (Exception e) {
- e.printStackTrace();
- }
- return conn;
- }
- }
- SpringConfig.class
- import org.springframework.context.annotation.Bean;
- import org.springframework.context.annotation.Configuration;
- @Configuration
- public class SpringConfig {
- @Bean("sqloperations")
- public SQLOperationJavaConfig sqLoperationJavaConfig() {
- DBConnection dbConnection=new AppJavaConfig<DBConnection>().getbean("dbconnection");
- return new SQLOperationJavaConfig(dbConnection);
- }
- @Bean("dbconnection")
- public DBConnection dbConnection() {
- return new DBConnection();
- }
- }
- SQLOperationJavaConfig.class
- public class SQLOperationJavaConfig {
- private DBConnection dbConnection;
- public SQLOperationJavaConfig(DBConnection dbConnection) {
- this.dbConnection=dbConnection;
- }
- private Connection conn;
- public void createTable() throws SQLException {
- conn = dbConnection.getDBConnection();
- String sql="drop table if exists dummy";
- String sql1 = "create table dummy (id int,name varchar(20))";
- Statement statement = conn.createStatement();
- statement.execute(sql);
- statement.execute(sql1);
- System.out.println("Table Created!!");
- }
- public void insertData() throws SQLException {
- conn = dbConnection.getDBConnection();
- String sql = "insert into dummy values(12,'Sunny')";
- Statement statement = conn.createStatement();
- statement.execute(sql);
- System.out.println("Record Inserted!!");
- }
- }
- public class AppJavaConfig<T> {
- static ApplicationContext context;
- public static void main(String[] args) throws SQLException {
- context = new AnnotationConfigApplicationContext(SpringConfig.class);
- SQLOperationJavaConfig sqLoperationJavaConfig = (SQLOperationJavaConfig) context.getBean("sqloperations");
- sqLoperationJavaConfig.createTable();
- sqLoperationJavaConfig.insertData();
- }
- public T getbean(String beanName) {
- T t=(T) context.getBean(beanName);
- return t;
- }
- }
- Caused by: java.lang.NullPointerException
- at com.src.springproj.AppJavaConfig.getbean(AppJavaConfig.java:17)
- at com.src.springproj.SpringConfig.sqLoperationJavaConfig(SpringConfig.java:10)
- return new SQLOperationJavaConfig(dbConnection());
- @autowired
- private DBConnection dbConnection;
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement