Question

我在下面的例子中有一个包含sql insert命令的字符串。

我想解析字段名称和值并将它们转换为JSON。

如何使用Java实现这一目标？

我在SQL中的SQL命令：

String sqlQuery = "INSERT INTO myTable (ID, CITY, STATE, LAT_N, LONG_W) VALUES " +
                  "(13, 'Phoenix', 'AZ', 33, 112); |\r\n" + 
                  "INSERT INTO myTable (ID, CITY, STATE, LAT_N, LONG_W) VALUES " +
                  "(44, 'Denver', 'CO', 40, 105); |\r\n" + 
                  "INSERT INTO myTable (ID, CITY, STATE, LAT_N, LONG_W) VALUES " +
                  "(66, 'Caribou', 'ME', 47, 68); |";

我期待如下输出：

{
    "fields": [{
        "ID": "13",
        "CITY": "Phoenix",
        "STATE": "AZ",
        "LAT_N": "33",
        "LONG_W": "112"
    }, {
        "ID": "44",
        "CITY": "Denver",
        "STATE": "CO",
        "LAT_N": "40",
        "LONG_W": "105"
    }, {
        "ID": "66",
        "CITY": "Caribou",
        "STATE": "ME",
        "LAT_N": "47",
        "LONG_W": "68"
    }]

}

Answer 1

这是将产生所需JSON格式输出的实际代码

我评论了每个部分的逻辑：

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class ToJson {

    public static void main(String[] args) {
        String sqlQuery = "INSERT INTO myTable (ID, CITY, STATE, LAT_N, LONG_W) VALUES (13, 'Phoenix', 'AZ', 33, 112); |\r\n" +
                "INSERT INTO myTable (ID, CITY, STATE, LAT_N, LONG_W) VALUES (44, 'Denver', 'CO', 40, 105); |\r\n" +
                "INSERT INTO myTable (ID, CITY, STATE, LAT_N, LONG_W) VALUES (66, 'Caribou', 'ME', 47, 68); |";

        //REMOVE UNNEEDED STUFF
        String trimUnwanted = sqlQuery.replaceAll("INSERT INTO myTable \\(ID, CITY, STATE, LAT_N, LONG_W\\) VALUES \\(", "")
                .replaceAll("'", "")
                .replaceAll("\\);", ""); 
        System.out.println("afterTrim: " + trimUnwanted);
        /*
        afterTrim: 13, Phoenix, AZ, 33, 112 |
        44, Denver, CO, 40, 105 |
        66, Caribou, ME, 47, 68 |
         */

        //SEPARATE INTO SEPARATE QUERIES
        String[] choppedUpText = trimUnwanted.split("\\|");
        System.out.println("Chopped up text >>");
        Arrays.stream(choppedUpText).forEach(System.out::println);

        //SEPARATE EACH QUERY INTO AN OBJECT, AND ADD TO LIST
        List<Address> list = new ArrayList<>();
        Arrays.stream(choppedUpText).forEach(s -> {
            System.out.println("adding -> "+ s);
            list.add(new Address(s.split(",")) ); //remember to do your error checking!
        }) ;

        String jsonStart = "{\n     \"fields\": " ;
        String jsonEnd = "\n\n}";

        //THE ACTUAL RESULT
        String json = jsonStart + list.toString() + jsonEnd;

        System.out.println(json);
    }

}

/* THE MAGIC CLASS  HANDLES THE PARSING AND DISPLAY */
class Address {

    String ID;
    String CITY;
    String STATE;
    String LAT_N;
    String LONG_W;

    public Address(String[] input) {
        this.ID = input[0].trim();
        this.CITY = input[1].trim();
        this.STATE = input[2].trim();
        this.LAT_N = input[3].trim();
        this.LONG_W = input[4].trim();
    }

    @Override
    public String toString() {
        //prints out in correct format
        return " {\n" +
                "        \"ID\": \""+ ID+ "\",\n" +
                "        \"CITY\": \""+ CITY+ "\",\n" +
                "        \"STATE\": \""+ STATE+ "\",\n" +
                "        \"LAT_N\": \""+ LAT_N+ "\",\n" +
                "        \"LONG_W\": \""+ LONG_W+ "\"\n" +
                "    }";
    }
}

上面代码的输出是：

afterTrim: 13, Phoenix, AZ, 33, 112 |
44, Denver, CO, 40, 105 |
66, Caribou, ME, 47, 68 |
Chopped up text >>
13, Phoenix, AZ, 33, 112 

44, Denver, CO, 40, 105 

66, Caribou, ME, 47, 68 
adding -> 13, Phoenix, AZ, 33, 112 
adding -> 
44, Denver, CO, 40, 105 
adding -> 
66, Caribou, ME, 47, 68 
{
     "fields": [ {
        "ID": "13",
        "CITY": "Phoenix",
        "STATE": "AZ",
        "LAT_N": "33",
        "LONG_W": "112"
    },  {
        "ID": "44",
        "CITY": "Denver",
        "STATE": "CO",
        "LAT_N": "40",
        "LONG_W": "105"
    },  {
        "ID": "66",
        "CITY": "Caribou",
        "STATE": "ME",
        "LAT_N": "47",
        "LONG_W": "68"
    }]

}

Answer 2

这是关于如何做到这一点的一种方法。这假设列名称是动态的。

从查询中删除所有单引号。
创建一个包含fields字段的类。
使用正则表达式+ java.util.Pattern + jave.util.Matcher在()之间提取项目。您将获得3个匹配，每个匹配将有2个组，一个具有列名称，另一个具有te值。
对于每个匹配：在逗号上拆分组，并将<column, column value>放入地图中。将此地图添加到列表中。
创建在步骤2中创建的对象的新实例，并将地图列表设置为fields值。
使用GSON或Jackson库将第5步中的实例转换为JSON。

将SQL命令转换为JSON参数格式

2 个答案: