使用Java 批量生成datax json 脚本

以下是使用Java批量生成DataX JSON脚本的示例代码：

import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

public class DataXJsonGenerator {

    public static void main(String[] args) {
        List<String> tables = new ArrayList<>();
        tables.add("table1");
        tables.add("table2");
        tables.add("table3");

        String sourceDbUrl = "jdbc:mysql://localhost:3306/source_db";
        String sourceDbUsername = "root";
        String sourceDbPassword = "password";

        String targetDbUrl = "jdbc:mysql://localhost:3306/target_db";
        String targetDbUsername = "root";
        String targetDbPassword = "password";

        for (String table : tables) {
            JSONObject job = new JSONObject();
            job.put("job", createJobObject(table));
            job.put("content", createContentObject(table, sourceDbUrl, sourceDbUsername, sourceDbPassword, targetDbUrl, targetDbUsername, targetDbPassword));

            try (FileWriter writer = new FileWriter(table + ".json")) {
                writer.write(job.toJSONString());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private static JSONObject createJobObject(String table) {
        JSONObject job = new JSONObject();
        job.put("setting", createSettingObject());
        job.put("content", createJobContentObject(table));
        return job;
    }

    private static JSONObject createSettingObject() {
        JSONObject setting = new JSONObject();
        setting.put("speed", createSpeedObject());
        return setting;
    }

    private static JSONObject createSpeedObject() {
        JSONObject speed = new JSONObject();
        speed.put("channel", 3);
        speed.put("byte", 1048576);
        return speed;
    }

    private static JSONObject createJobContentObject(String table) {
        JSONObject content = new JSONObject();
        content.put("reader", createReaderObject(table));
        content.put("writer", createWriterObject(table));
        return content;
    }

    private static JSONObject createReaderObject(String table) {
        JSONObject reader = new JSONObject();
        reader.put("name", "mysqlreader");
        reader.put("parameter", createReaderParameterObject(table));
        return reader;
    }

    private static JSONObject createReaderParameterObject(String table) {
        JSONObject parameter = new JSONObject();
        parameter.put("username", "root");
        parameter.put("password", "password");
        parameter.put("column", createReaderColumnObject(table));
        parameter.put("connection", createReaderConnectionObject());
        parameter.put("where", "1=1");
        parameter.put("splitPk", "id");
        parameter.put("table", table);
        return parameter;
    }

    private static JSONObject createReaderColumnObject(String table) {
        JSONObject column = new JSONObject();
        column.put("id", "bigint");
        column.put("name", "varchar");
        column.put("age", "int");
        column.put("address", "varchar");
        return column;
    }

    private static JSONObject createReaderConnectionObject() {
        JSONObject connection = new JSONObject();
        connection.put("jdbcUrl", "jdbc:mysql://localhost:3306/source_db");
        connection.put("table", new ArrayList<>());
        return connection;
    }

    private static JSONObject createWriterObject(String table) {
        JSONObject writer = new JSONObject();
        writer.put("name", "mysqlwriter");
        writer.put("parameter", createWriterParameterObject(table));
        return writer;
    }

    private static JSONObject createWriterParameterObject(String table) {
        JSONObject parameter = new JSONObject();
        parameter.put("username", "root");
        parameter.put("password", "password");
        parameter.put("column", createWriterColumnObject(table));
        parameter.put("preSql", "TRUNCATE TABLE " + table);
        parameter.put("connection", createWriterConnectionObject());
        parameter.put("table", table);
        return parameter;
    }

    private static JSONObject createWriterColumnObject(String table) {
        JSONObject column = new JSONObject();
        column.put("id", "bigint");
        column.put("name", "varchar");
        column.put("age", "int");
        column.put("address", "varchar");
        return column;
    }

    private static JSONObject createWriterConnectionObject() {
        JSONObject connection = new JSONObject();
        connection.put("jdbcUrl", "jdbc:mysql://localhost:3306/target_db");
        return connection;
    }

    private static JSONObject createContentObject(String table, String sourceDbUrl, String sourceDbUsername, String sourceDbPassword, String targetDbUrl, String targetDbUsername, String targetDbPassword) {
        JSONObject content = new JSONObject();
        content.put("job", createContentJobObject(table));
        content.put("source", createContentSourceObject(sourceDbUrl, sourceDbUsername, sourceDbPassword));
        content.put("destination", createContentDestinationObject(targetDbUrl, targetDbUsername, targetDbPassword));
        return content;
    }

    private static JSONObject createContentJobObject(String table) {
        JSONObject job = new JSONObject();
        job.put("content", createJobContentObject(table));
        job.put("setting", createSettingObject());
        return job;
    }

    private static JSONObject createContentSourceObject(String sourceDbUrl, String sourceDbUsername, String sourceDbPassword) {
        JSONObject source = new JSONObject();
        source.put("jdbcUrl", sourceDbUrl);
        source.put("username", sourceDbUsername);
        source.put("password", sourceDbPassword);
        return source;
    }

    private static JSONObject createContentDestinationObject(String targetDbUrl, String targetDbUsername, String targetDbPassword) {
        JSONObject destination = new JSONObject();
        destination.put("jdbcUrl", targetDbUrl);
        destination.put("username", targetDbUsername);
        destination.put("password", targetDbPassword);
        return destination;
    }
}

这个示例代码将生成三个DataX JSON脚本，分别对应三个表格。在这个示例中，我们使用了fastjson库来创建JSON对象。使用时，需要将fastjson库添加到项目的依赖中。

此外，在这个示例中，我们将所有的配置都硬编码在代码中，但实际使用时，可能需要将它们存储在配置文件或数据库中，并在生成JSON脚本时读取它们