userdao.java

spring2.0技术手册随书事例,结合例子学习起来更轻松

package onlyfun.caterpillar;

import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.
            datasource.DataSourceTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.
            support.DefaultTransactionDefinition;

public class UserDAO implements IUserDAO {
    private DataSourceTransactionManager transactionManager;
    private DefaultTransactionDefinition def;
    private JdbcTemplate jdbcTemplate;
    
    public void setDataSource(DataSource dataSource) {
        jdbcTemplate = new JdbcTemplate(dataSource);
        transactionManager = 
            new DataSourceTransactionManager(dataSource);
        //建立事务的定义
        def = new DefaultTransactionDefinition();
        def.setPropagationBehavior(
                TransactionDefinition.PROPAGATION_REQUIRED);
    }
    
    public void insert(User user) {
       String name = user.getName();
       int age = user.getAge().intValue();
       
       TransactionStatus status = 
           transactionManager.getTransaction(def);
       try {
           jdbcTemplate.update("INSERT INTO user (name,age) " 
                   + "VALUES('" + name + "'," + age + ")");
           //下面的SQL有错误，用以测试事务
           jdbcTemplate.update("INSER INTO user (name,age) " 
                   + "VALUES('" + name + "'," + age + ")");
       }
       catch(DataAccessException e) {
           transactionManager.rollback(status);
           throw e; 
       }
       transactionManager.commit(status);
    }

    public User find(Integer id) {
        List rows = jdbcTemplate.queryForList(
          "SELECT * FROM user WHERE id=" + id.intValue());
        
        Iterator it = rows.iterator();
        if(it.hasNext()) {
            Map userMap = (Map) it.next();
            Integer i = new Integer(
                    userMap.get("id").toString());
            String name = userMap.get("name").toString();
            Integer age = new Integer(
                    userMap.get("age").toString());

            User user = new User();
            
            user.setId(i);
            user.setName(name);
            user.setAge(age);
            
            return user;
        }

        return null;
    }
}