jdbctemplate 获取数据表结构的方法&注意事项

方法一 直接查询：

SqlRowSet srcSqlRowSet = srcJdbcTemplate.queryForRowSet("SELECT * FROM tablename LIMIT 0"); //注意limit 0更合适
List<ColumnMetaData> columneMetaList = new LinkedList<ColumnMetaData>();
int columnCount;
SqlRowSetMetaData sqlRowSetMetaData = sqlRowSet.getMetaData();
columnCount = sqlRowSetMetaData.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
columneMetaList.add(new ColumnMetaData(sqlRowSetMetaData.getColumnName(i), sqlRowSetMetaData.getColumnType(i), sqlRowSetMetaData.getColumnTypeName(i))); //获取字段的名称、类型和描述
}
Collections.sort(columneMetaList);

方法一的ColumnMetaData类代码如下：

public class ColumnMetaData implements Comparable<ColumnMetaData> {

private String name; // 字段名称
private int type; // 字段类型
private String typeName; // 字段类型名称
private Object value; // 值

public ColumnMetaData(String columnName, int valueType, String typeName) {
this.name = columnName;
this.type = valueType;
this.typeName = typeName;
}
}

方法二 使用RowCountCallbackHandler查询

String sql = "select * from "+ tableName + " limit 0";
RowCountCallbackHandler rcch = new RowCountCallbackHandler();
this.jdbcTemplateDao.query(sql, rcch);
String[] coloumnName = rcch.getColumnNames();
int[] coloumnType = rcch.getColumnTypes();

方法二效率高，但麻烦的是拿到了类型是数字，如果要获得字段的描述信息，比如：int还是varchar等，需要一个对照关系类：

public class SqlTypeAdapter {
public static String getTypeName(int type) throws SQLException {
switch (type) {
case Types.ARRAY:
break;
case Types.BIGINT:
return "BIGINT";
case Types.BINARY:
return "BINARY";
case Types.BIT:
return "BIT";
case Types.BLOB:
return "BLOB";
case Types.BOOLEAN:
return "BOOLEAN";
//..代码太多就不多写啦default:
break;
}
return "VARCHAR";
}
}