com.ktanx.autocoder.db.AbstractDatabaseProcessor Maven / Gradle / Ivy

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package com.ktanx.autocoder.db;

import com.ktanx.autocoder.config.ColumnMetaData;
import com.ktanx.autocoder.config.JdbcConfig;
import com.ktanx.autocoder.config.TableMetaData;
import com.ktanx.common.exception.KtanxException;
import org.apache.commons.lang3.StringUtils;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public abstract class AbstractDatabaseProcessor implements DatabaseProcessor {

    protected Connection connection;

    private void initConnection(JdbcConfig jdbcConfig) {
        try {
            if (connection != null && !connection.isClosed()) {
                return;
            }
            Class.forName(jdbcConfig.getDriverClassName());
            connection = DriverManager.getConnection(jdbcConfig.getUrl(), jdbcConfig.getUsername(), jdbcConfig.getPassword());
        } catch (ClassNotFoundException e) {
            throw new KtanxException("Did not find the database driver class,whether to add the database driver jar ?");
        } catch (SQLException e) {
            throw new KtanxException("Create database connection error");
        }
    }


    /**
     * 获取数据库表的信息
     *
     * @param tableName 表名
     * @return meta data
     */
    public TableMetaData getTableMetaData(String tableName, JdbcConfig jdbcConfig) {

        try {
            initConnection(jdbcConfig);
            TableMetaData.TableMetaDataBuilder builder = TableMetaData.builder();
            String pkName = this.getPkName(tableName,connection);
            Map columnComments = this.getColumnComments(tableName,connection);
            tableName = this.getSelectTableName(tableName);
            List columnList = new ArrayList<>();

            //查询时没有数据，只返回表头信息
            PreparedStatement pst = connection.prepareStatement("select * from " + tableName + " where 1=2");
            ResultSetMetaData rsd = pst.executeQuery().getMetaData();

            for (int i = 1; i <= rsd.getColumnCount(); i++) {
                String name = rsd.getColumnName(i);
                String dbType = rsd.getColumnTypeName(i);
                String javaClass = rsd.getColumnClassName(i);
                int nullable = rsd.isNullable(i);
                int columnDisplaySize = rsd.getColumnDisplaySize(i);
                int scale = rsd.getScale(i);
                boolean autoIncrement = rsd.isAutoIncrement(i);

                boolean isPk = StringUtils.equalsIgnoreCase(pkName, name) ? true : false;

                ColumnMetaData columnMetaData = ColumnMetaData.builder()
                        .name(name)
                        .dbType(dbType)
                        .jdbcType(dbType)
                        .javaType(javaClass)
                        .isNullable(nullable == 1 ? true : false)
                        .displaySize(columnDisplaySize)
                        .scale(scale)
                        .isAutoIncrement(autoIncrement)
                        .comment(columnComments == null ? "" : columnComments.get(name))
                        .isPk(isPk)
                        .build();

                columnList.add(columnMetaData);
            }
            pst.close();
            TableMetaData tableMetaData = builder.name(tableName)
                    .columns(columnList)
                    .comment(this.getTableComment(tableName,connection))
                    .build();
            return tableMetaData;
        } catch (Exception e) {
            throw new KtanxException(e);
        }

    }

    /**
     * 获取select查询sql使用的表名,一般情况下无需处理,必要时重写
     * 只有当表名跟系统表名或关键字一样时,需要加工下
     * 例如postgresql中USER表,必须是select * from "USER" —> 和系统表名重合需要加双引号
     *
     * @param tableName the table name
     * @return select table name
     */
    protected String getSelectTableName(String tableName) {
        return tableName;
    }

    /**
     * 获取表备注
     *
     * @param tableName  the table name
     * @param connection the connection
     * @return table comment
     * @throws SQLException the sQL exception
     */
    protected String getTableComment(String tableName, Connection connection) throws SQLException {
        return "";
    }

    /**
     * 获取主键名
     *
     * @param tableName  the table name
     * @param connection the connection
     * @return pk name
     * @throws SQLException the sQL exception
     */
    protected abstract String getPkName(String tableName, Connection connection) throws SQLException;

    /**
     * 获取列注释
     *
     * @param tableName  the table name
     * @param connection the connection
     * @return column comments
     * @throws SQLException the sQL exception
     */
    protected abstract Map getColumnComments(String tableName, Connection connection) throws SQLException;
}