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public String selectSingleLineToJson(String sql) {// 查询数据,返回String,再组合成json
try {
statement = connection.createStatement();
resultSet = statement.executeQuery(sql);
ResultSetMetaData rsmd = resultSet.getMetaData();// 计算字段个数
int col = rsmd.getColumnCount(); // 获得总列数
String selectItems[] = new String[col];// 创建对象,存储结果,以返回
resultSet.next();
StringBuilder sb = new StringBuilder("{");
for (int j = 0; j < col; j++)
sb.append("\"" + rsmd.getColumnName(j + 1) + "\":\""
+ resultSet.getString(j + 1) + "\",");
sb.delete(sb.length() - 1, sb.length());
sb.append("}");
resultSet.close();
return sb.toString();
} catch (SQLException e) {
e.printStackTrace();
}
return "{\"flag\":\"false\"}";// 出错处理
}
public String selectMultiLineToJson(String sql) {// 查询数据,返回多个String数组,再组合成json数组
try {
statement = connection.createStatement();
resultSet = statement.executeQuery(sql);
ResultSetMetaData rsmd = resultSet.getMetaData();//
int col = rsmd.getColumnCount(); // 获得总列数
StringBuilder sb = new StringBuilder("[");
for (int i = 0; resultSet.next(); i++) {
sb.append("{");
for (int j = 0; j < col; j++)
sb.append("\"" + rsmd.getColumnName(j + 1) + "\":\""
+ resultSet.getString(j + 1) + "\",");
sb.delete(sb.length() - 1, sb.length());
sb.append("},");
}
sb.delete(sb.length() - 1, sb.length());
if (sb.toString().equals(""))
return "[{\"flag\":\"false\"}]";// 结果为空,出错处理;
sb.append("]");
resultSet.close();
//System.out.println(sb.toString());
return sb.toString();
} catch (SQLException e) {
e.printStackTrace();
}
return "[{\"flag\":\"false\"}]";// 出错处理
}