问题解决：DATABASEMETADATA.GETTABLES()方法，返回了所有库中的表

水深无声 2022-09-10 08:19 289阅读 1赞

本地代码

//获取表所有字段
    private List<String> getFieldListFromConnectMetaData(@NonNull DatabaseConnectModel model, String tableName) {
            try {
                Class.forName(model.getDriverClassName());
                Connection connection = DriverManager.getConnection(model.getUrl(),
                        model.getUsername(), model.getPassword());
                ResultSet rs = connection.getMetaData().getColumns(null, null, tableName, null);
                List<String> fieldNameList = Lists.newArrayList();
                while (rs.next()) {
                    fieldNameList.add(rs.getString("COLUMN_NAME"));
                }
                return fieldNameList;
            } catch (ClassNotFoundException | SQLException e) {
                throw new RuntimeException(e.getMessage(), e);
            }
        }
    
    //获取库所有表
    private List<String> getTableListFromConnectMetaData(@NonNull DatabaseConnectModel model) {
            try {
                Class.forName(model.getDriverClassName());
                Connection connection = DriverManager.getConnection(model.getUrl(),
                        model.getUsername(), model.getPassword());
                ResultSet rs = connection.getMetaData().getTables(null, null, "%", new String[]{});
                List<String> tableNameList = Lists.newArrayList();
                while (rs.next()) {
                    tableNameList.add(rs.getString("TABLE_NAME"));
                }
                return tableNameList;
            } catch (ClassNotFoundException | SQLException e) {
                throw new RuntimeException(e.getMessage(), e);
            }
        }

返回的字段列和表都是重复的

`DatabaseMetaData .getTables()`方法常常用来获取数据库中的所有表信息。  
但我想要获取我的本地数据库`db_test`中的表信息，出现了错误。

# **解决方案** #

mysql8.0的驱动，在5.5之前`nullCatalogMeansCurrent`属性默认为`true`,8.0中默认为`false`，[官网链接地址。][Link 1]所以导致`DatabaseMetaData.getTables()`加载了全部的无关表。

解决方法是，在jdbc 创建连接的url后加上`&nullCatalogMeansCurrent=true`

[Link 1]: https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-properties-changed.html