jdbctemplate 獲取數據表結構的方法&注意事項

方法一 直接查詢：

SqlRowSet srcSqlRowSet = srcJdbcTemplate.queryForRowSet("SELECT * FROM tablename LIMIT 0"); //注意limit 0更合適
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))); //獲取字段的名稱、類型和描述
}
Collections.sort(columneMetaList);

方法一的ColumnMetaData類代碼如下：

public class ColumnMetaData implements Comparable<ColumnMetaData> {

    private String name; // 字段名稱
    private int type; // 字段類型
    private String typeName; // 字段類型名稱
    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查詢

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，但麻煩的是拿到了類型是數字，如果要獲得字段的描述信息，比如：int還是varchar等，需要一個對照關系類：

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";
            //..代碼太多就不多寫啦default:
                break;
        }
        return "VARCHAR";
    }
}