1、JDBC将返回结果集封装成对象demo
class JdbcDemo {
/**
* 获取数据库列名
* @param rs
* @return
*/
private static String[] getColNames(ResultSet rs) throws SQLException {
ResultSetMetaData rsmd = rs.getMetaData();
//获取查询的列数
int count = rsmd.getColumnCount();
String[] colNames = new String[count];
for(int i = 1; i <= count; i ++) {
//获取列名
colNames[i - 1] = rsmd.getColumnLabel(i);
}
return colNames;
}
/**
* 将JDBC查询返回的结果集，利用反射封装成对象
* @param sql
* @param clazz
* @return
*/
private static Object getObject(String sql, Class clazz) {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = JdbcUtils.getConnection();
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
String[] colNames = getColNames(rs);
Object object = null;
Method[] ms = clazz.getMethods();
if(rs.next()) {
object = clazz.newInstance();
for(int i = 0; i < colNames.length; i ++) {
String colName = colNames[i];
String methodName = "set" + colName;
//稳妥一点。在对象查询下是否有此方法在调用方法
for(Method md : ms) {
if(methodName.equals(md.getName())) {
md.invoke(object, rs.getObject(colName));
break;
}
}
}
}
return object;
} finally {
//释放连接
JdbcUtils.free(rs, ps, conn);
}
}
}