数据库数据 java对象_是用JDBC从数据库中获取数据并以java对象返回

/**

*

* @param c

* for example Person.class

* @param primaryKeys

* primaryKeys为主键,参数顺序和表中保持一致 如果id， name 为主键 类名为Person 则 getEntity(Person.class,1,"name")

* @return

*/

public static Object getEntity(Class c, Object... primaryKeys) {

PreparedStatement ps = null;

ResultSet rs = null;

DatabaseMetaData dmd = null;

Object obj = null;// 要返回的对象

String tableName = c.getSimpleName().toLowerCase();// person 表的名字

List primaryKeyNameList = new ArrayList();

Field[] fields = c.getFields();// 获取所有的属性

StringBuilder sql = new StringBuilder("select * from " + tableName

+ " where ");

try {

obj = c.newInstance();

dmd = getConnection().getMetaData();

rs = dmd.getPrimaryKeys(null, null, tableName);

while (rs.next()) {

sql.append(rs.getObject(4) + "=?");

sql.append(" and ");

primaryKeyNameList.add(rs.getObject(4));// 将从表中获取的 主键字段存到 list中， 主键位于表中第几列=rs.getString(5)

}

sql.delete(sql.length() - 4, sql.length());

ps = (PreparedStatement) getConnection().prepareStatement(

sql.toString());

for (int l = 0; l < primaryKeyNameList.size(); l++) {

ps.setObject(l + 1, primaryKeys[l]);

}

rs = ps.executeQuery();

System.out.println(ps.toString().split(":")[1]);

if (rs.next()) {

for (int k = 0; k < fields.length; k++) {

fields[k].set(obj, rs.getObject(k + 1));

}

}

rs.close();

ps.close();

rs=null;

ps=null;

} catch (Exception e) {

e.printStackTrace();

} finally {

}

return obj;

}