Java实现读A数据库返回JSONArray格式，写入B数据库

复制即可使用

只需要修改两个数据库连接方式即可

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import java.sql.*;

public class DateToDate {
    
    public static String PRE_USER = "root";
    public static String PRE_PASSWORD = "123456";
    public static String PRE_DBDRIVER = "com.mysql.cj.jdbc.Driver";
    public static String PRE_DBURL = "jdbc:mysql://127.0.0.1:3306/stw_ckd?characterEncoding=utf8&useSSL=false&serverTimezone=UTC";

    
    public static String IN_USER = "root";
    public static String IN_PASSWORD = "123456";
    public static String IN_DBDRIVER = "com.mysql.cj.jdbc.Driver";
    public static String IN_DBURL = "jdbc:mysql://127.0.0.1:3306/stw_ckd?characterEncoding=utf8&useSSL=false&serverTimezone=UTC";


    public static void main(String[] args) {
        //读取数据库sql
        String sql ="select * from patient_his_rel";
        JSonArray jsonArray = select(sql);
        if (jsonArray.size() > 0) {
            for (int i = 0; i < jsonArray.size(); i++) {
                JSonObject obj = jsonArray.getJSonObject(i);
                update("REPLACE INTO patient_his_rel_copy" +
                        "(patient_id, his_patient_id, pat_tag, pat_state, create_time) " +
                        String.format("VALUES(%s, %s, %s, %s, %s);",
                                getVarcharParameter(obj.getString("patient_id")),
                                getVarcharParameter(obj.getString("his_patient_id")),
                                getVarcharParameter(obj.getString("pat_tag")),
                                getVarcharParameter(obj.getString("pat_state")),
                                getVarcharParameter(obj.getString("create_time"))
                        ));
            }
        }
    }


    
    public static JSonArray select(String sql){
        JSonArray jsonArray = null;
        try{
            Class.forName(PRE_DBDRIVER);
            Connection connection = DriverManager.getConnection(PRE_DBURL, PRE_USER, PRE_PASSWORD);
            Statement statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery(sql);
            jsonArray = resultToJsa(resultSet);
            resultSet.close();
            statement.close();
            connection.close();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
        return jsonArray;
    }

    public static void update(String sql) {
        try {
            Class.forName(IN_DBDRIVER);
            Connection connection = DriverManager.getConnection(IN_DBURL, IN_USER, IN_PASSWORD);
            Statement statement = connection.createStatement();
            statement.executeUpdate(sql);
            statement.close();
            connection.close();
        } catch (SQLException | ClassNotFoundException throwables) {
            throwables.printStackTrace();
        }
    }

    
    private static JSonArray resultToJsa(ResultSet resultSet) {
        JSonArray jsonArray = new JSonArray();
        try {
            ResultSetmetaData metaData = resultSet.getmetaData();
            int columnCount = metaData.getColumnCount();
            JSonObject jsonObject = null;
            while (resultSet.next()){
                jsonObject = new JSonObject();
                for (int i = 1;i<=columnCount; i++){
                    String columnName = metaData.getColumnName(i);
                    jsonObject.put(columnName, resultSet.getString(i));
                }
                jsonArray.add(jsonObject);
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return jsonArray;
    }

    public static String getVarcharParameter(String s){
        if(s != null && s.length() > 0){
            return "'" + s + "'";
        }else{
            return "null";
        }
    }

}