利用回调简化JDBC编程
简单看了一下spring 的jdbc支持，现在又要直接用到jdbc，想想就是痛苦。于是参考了spring，自己写了一些简单的java封装类来简化编程。
废话少说，我这里就用代码来代言吧，看看怎样简化我们的JDBC编程，可以和以前进行对比。
(1） JdbcTemplate。
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;import javax.sql.DataSource;import org.winter.util.DBUtil;/**
* a simple JDBC template 模仿spring的JdbcTemplate
*
* @author bluestone
* @version 1.0 2006-8-8
*
*/
public class JdbcTemplate { private DataSource dataSource = null; public JdbcTemplate(DataSource ds) {
this.dataSource = ds;
}/**
* 执行更新操作
*
* @param sql
* @param setter
* @return
* @throws SQLException
*/
public int update(String sql, PreparedStatementSetter setter)
throws SQLException {
Connection conn = null;
reparedStatement ps = null;
try {
conn = dataSource.getConnection();
ps = conn.prepareStatement(sql);
setter.setValues(ps);
return ps.executeUpdate();
} finally {
DBUtil.colseConnection(conn, ps, null);
}
} /**
*
* @param sql
* @return
* @throws SQLException
*/
public boolean execute(String sql) throws SQLException {
Connection conn = null;
Statement stmt = null;
try {
conn = dataSource.getConnection();
stmt = conn.createStatement();
return stmt.execute(sql);
} finally {
DBUtil.colseConnection(conn, stmt, null);
}
} /**
*
* @param sql
* @param setter
* @param extractor
* @return
* @throws SQLException
*/
public Object query(String sql, PreparedStatementSetter setter,
ResultSetExtractor extractor) throws SQLException {
Connection conn = null;
reparedStatement ps = null;
ResultSet rs = null;
try {
conn = dataSource.getConnection();
ps = conn.prepareStatement(sql);
setter.setValues(ps);
rs = ps.executeQuery();
return extractor.extractData(rs);
} finally {
DBUtil.colseConnection(conn, ps, rs);
}
} // .........................
}(2) PreparedStatementSetterpublic interface PreparedStatementSetter {
void setValues(PreparedStatement ps) throws SQLException;
}(3)
ResultSetExtractorpublic interface ResultSetExtractor {
Object extractData(ResultSet rs) throws SQLException;
}(4) 可以参考spring自己定义其他接口。。。
用了这些辅助类，我们就可以像用spring那样编程了（当然这只能用在对事务要求不高的应用环境中）。看看怎么使用：
private JdbcTemplate template; public JobManageDao() throws BusinessException {
try {
template = new JdbcTemplate(DBHelper.getDataSource());
} catch (NamingException e) {
throw new BusinessException(e);
}
}public long saveJobInfo(final JobInfo info) throws BusinessException {
final long id = IdGenerator.getIdLong();
try {
int j = template.update(INSERT_JOB_SQL, new PreparedStatementSetter() { public void setValues(PreparedStatement ps) throws SQLException {
int i = 1;
ps.setLong(i++, id); //...... }
});
return j > 0 ? id : 0L;
} catch (SQLException e) {
throw new BusinessException(e);
}
}