Spring事物處理（代碼實現）

TransactionTemplate這個類是Spring的事務處理模板,在它的execute()方法裏定義事務處理的骨架代碼.

但execute()方法的TransactionCallback參數倒是個接口,在這接口中定義了doInTransaction()方法

只要實現TransactionCallback接口,並在doInTransaction()方法裏編寫具體要進行的事務處理的代碼就能夠 了.

代碼截圖

 

 

import java.sql.ResultSet;
import java.sql.SQLException;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionTemplate;

import com.sunflower.entity.People;


public class BankDaoImp implements BankDao {
	private JdbcTemplate jdbcTemplate;
	private TransactionTemplate transactionTemplate;

	public JdbcTemplate getJdbcTemplate() {
		return jdbcTemplate;
	}

	public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
		this.jdbcTemplate = jdbcTemplate;
	}

	public TransactionTemplate getTransactionTemplate() {
		return transactionTemplate;
	}

	public void setTransactionTemplate(TransactionTemplate transactionTemplate) {
		this.transactionTemplate = transactionTemplate;
	}

	@Override
	public double getMoney(final People people) {
		double money = people.getMoney();
		// 開始事務，若是出現情況則回滾
		transactionTemplate.execute(new TransactionCallback<People>() {
			@Override
			public People doInTransaction(TransactionStatus ts) {
				try {
					final People people2 = new People();
					// 使用JdbcTemplate進行持久化層操做
					String sql = "select money from bank where name = ?";
					Object[] params = new Object[] { people.getName() };
					// 查詢
					jdbcTemplate.query(sql, params, new RowCallbackHandler() {
						@Override
						public void processRow(ResultSet rs)
								throws SQLException {
							people2.setMoney(rs.getDouble("money"));
							System.out.println(people.getName() + "用戶還有"
									+ rs.getDouble("money") + "元餘款");
							System.out.println(people.getName() + "要從帳戶中取出"
									+ people.getMoney() + "元");
							if (people2.getMoney() < people.getMoney()) {
								System.out.println("餘額不足");
								people.setMoney(-1);
								return;
							}
						}
					});

					if (people.getMoney() < 0)
						return null;
					else {
						sql = "update bank set money = ? where name = ?";
						Object[] params2 = new Object[] {
								people2.getMoney() - people.getMoney(),
								people.getName() };
						jdbcTemplate.update(sql, params2);
						System.out.println("剩餘餘額:"
								+ (people2.getMoney() - people.getMoney()));
					}
				} catch (Exception e) {
					ts.setRollbackOnly();
				}

				// 若是成功，事務被提交
				return people;
			}
		});

		return people.getMoney();
	}
}