【Java】JSONの扱い(1) – ファイルを読み込んでオブジェクトに変換

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven</groupId>
  <artifactId>maven</artifactId>
  <version>0.0.1-SNAPSHOT</version>

<dependencies>
  <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.17.0</version>
  </dependency>
</dependencies>

</project>

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

<groupId>maven</groupId>

<artifactId>maven</artifactId>

<version>0.0.1-SNAPSHOT</version>

<groupId>com.fasterxml.jackson.core</groupId>

<artifactId>jackson-databind</artifactId>

</dependency>

</dependencies>

</project>

package yurufuwa.prog.sample;

import java.io.File;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTest {

	public static void main(String[] args) {

		try {
			//JSONファイルを読み込んで、オブジェクトに変換
			File srcFile = new File("d:\\work\\input.json");

			ObjectMapper om = new ObjectMapper();
			Pref pref = om.readValue(srcFile, Pref.class);

			//読み込んだ結果を出力
			System.out.println("--読み込んだPref--");
			System.out.println("kenCode:" + pref.getKenCode());
			System.out.println("kenName:" + pref.getKenName());
			System.out.println("yomigana:" + pref.getYomigana());

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

package yurufuwa.prog.sample;

import java.io.File;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTest {

public static void main(String[] args) {

try {

//JSONファイルを読み込んで、オブジェクトに変換

File srcFile = new File("d:\\work\\input.json");

ObjectMapper om = new ObjectMapper();

Pref pref = om.readValue(srcFile, Pref.class);

//読み込んだ結果を出力

System.out.println("--読み込んだPref--");

System.out.println("kenCode:" + pref.getKenCode());

System.out.println("kenName:" + pref.getKenName());

System.out.println("yomigana:" + pref.getYomigana());

} catch (Exception e) {

e.printStackTrace();

}

package yurufuwa.prog.sample;

public class Pref {

	private String kenCode = null;
	private String kenName = null;
	private String yomigana = null;

	public String getKenCode() {
		return kenCode;
	}
	public void setKenCode(String kenCode) {
		this.kenCode = kenCode;
	}
	public String getKenName() {
		return kenName;
	}
	public void setKenName(String kenName) {
		this.kenName = kenName;
	}
	public String getYomigana() {
		return yomigana;
	}
	public void setYomigana(String yomigana) {
		this.yomigana = yomigana;
	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

package yurufuwa.prog.sample;

public class Pref {

private String kenCode = null;

private String kenName = null;

private String yomigana = null;

public String getKenCode() {

return kenCode;

}

public void setKenCode(String kenCode) {

this.kenCode = kenCode;

}

public String getKenName() {

return kenName;

}

public void setKenName(String kenName) {

this.kenName = kenName;

}

public String getYomigana() {

return yomigana;

}

public void setYomigana(String yomigana) {

this.yomigana = yomigana;

}

{
	"kenCode" : "01",
	"kenName" : "北海道",
	"yomigana" : "ほっかいどう"
}

1

2

3

4

5

{

"kenCode" : "01",

"kenName" : "北海道",

"yomigana" : "ほっかいどう"

}

package yurufuwa.prog.sample;

import java.io.File;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTest2 {

	public static void main(String[] args) {

		try {
			//JSONファイルを読み込んで、オブジェクトに変換
			File srcFile = new File("d:\\work\\input.json");

			ObjectMapper om = new ObjectMapper();
			PrefList prefList = om.readValue(srcFile, PrefList.class);

			//読み込んだ結果を出力
			for(Pref pref : prefList.getPrefList()) {
				System.out.println("--読み込んだPref--");
				System.out.println("kenCode:" + pref.getKenCode());
				System.out.println("kenName:" + pref.getKenName());
				System.out.println("yomigana:" + pref.getYomigana());
			}

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

package yurufuwa.prog.sample;

import java.io.File;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTest2 {

public static void main(String[] args) {

try {

//JSONファイルを読み込んで、オブジェクトに変換

File srcFile = new File("d:\\work\\input.json");

ObjectMapper om = new ObjectMapper();

PrefList prefList = om.readValue(srcFile, PrefList.class);

//読み込んだ結果を出力

for(Pref pref : prefList.getPrefList()) {

System.out.println("--読み込んだPref--");

System.out.println("kenCode:" + pref.getKenCode());

System.out.println("kenName:" + pref.getKenName());

System.out.println("yomigana:" + pref.getYomigana());

}

} catch (Exception e) {

e.printStackTrace();

}

package yurufuwa.prog.sample;

public class Pref {

	private String kenCode = null;
	private String kenName = null;
	private String yomigana = null;

	public String getKenCode() {
		return kenCode;
	}
	public void setKenCode(String kenCode) {
		this.kenCode = kenCode;
	}
	public String getKenName() {
		return kenName;
	}
	public void setKenName(String kenName) {
		this.kenName = kenName;
	}
	public String getYomigana() {
		return yomigana;
	}
	public void setYomigana(String yomigana) {
		this.yomigana = yomigana;
	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

package yurufuwa.prog.sample;

public class Pref {

private String kenCode = null;

private String kenName = null;

private String yomigana = null;

public String getKenCode() {

return kenCode;

}

public void setKenCode(String kenCode) {

this.kenCode = kenCode;

}

public String getKenName() {

return kenName;

}

public void setKenName(String kenName) {

this.kenName = kenName;

}

public String getYomigana() {

return yomigana;

}

public void setYomigana(String yomigana) {

this.yomigana = yomigana;

}

package yurufuwa.prog.sample;

import java.util.List;

public class PrefList {

	List<Pref> prefList = null;

	public List<Pref> getPrefList() {
		return prefList;
	}

	public void setPrefList(List<Pref> prefList) {
		this.prefList = prefList;
	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

package yurufuwa.prog.sample;

import java.util.List;

public class PrefList {

List<Pref> prefList = null;

public List<Pref> getPrefList() {

return prefList;

}

public void setPrefList(List<Pref> prefList) {

this.prefList = prefList;

}

{
	"prefList" : [
		{
			"kenCode" : "01",
			"kenName" : "北海道",
			"yomigana" : "ほっかいどう"
		},
		{
			"kenCode" : "02",
			"kenName" : "青森県",
			"yomigana" : "あおもりけん"
		},
		{
			"kenCode" : "03",
			"kenName" : "岩手県",
			"yomigana" : "いわてけん"
		}
	]
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

{

"prefList" : [

{

"kenCode" : "01",

"kenName" : "北海道",

"yomigana" : "ほっかいどう"

},

{

"kenCode" : "02",

"kenName" : "青森県",

"yomigana" : "あおもりけん"

},

{

"kenCode" : "03",

"kenName" : "岩手県",

"yomigana" : "いわてけん"

}

]

}

package yurufuwa.prog.sample;

import java.io.File;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTest3 {

	public static void main(String[] args) {

		try {
			//JSONファイルを読み込んで、オブジェクトに変換
			File srcFile = new File("d:\\work\\input.json");

			ObjectMapper om = new ObjectMapper();
			PrefList prefList = om.readValue(srcFile, PrefList.class);

			//読み込んだ結果を出力
//			for(Pref pref : prefList.getPrefList()) {
//				System.out.println("kenCode:" + pref.getKenCode());
//				System.out.println("kenName:" + pref.getKenName());
//				System.out.println("yomigana:" + pref.getYomigana());
//				System.out.println("--");
//			}

			//JSONファイルに書き込み
			File destFile = new File("d:\\work\\output.json");

			om.writeValue(destFile, prefList);

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

package yurufuwa.prog.sample;

import java.io.File;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTest3 {

public static void main(String[] args) {

try {

//JSONファイルを読み込んで、オブジェクトに変換

File srcFile = new File("d:\\work\\input.json");

ObjectMapper om = new ObjectMapper();

PrefList prefList = om.readValue(srcFile, PrefList.class);

//読み込んだ結果を出力

// for(Pref pref : prefList.getPrefList()) {

// System.out.println("kenCode:" + pref.getKenCode());

// System.out.println("kenName:" + pref.getKenName());

// System.out.println("yomigana:" + pref.getYomigana());

// System.out.println("--");

// }

//JSONファイルに書き込み

File destFile = new File("d:\\work\\output.json");

om.writeValue(destFile, prefList);

} catch (Exception e) {

e.printStackTrace();

}

package yurufuwa.prog.sample;

public class Pref {

	private String kenCode = null;
	private String kenName = null;
	private String yomigana = null;

	public String getKenCode() {
		return kenCode;
	}
	public void setKenCode(String kenCode) {
		this.kenCode = kenCode;
	}
	public String getKenName() {
		return kenName;
	}
	public void setKenName(String kenName) {
		this.kenName = kenName;
	}
	public String getYomigana() {
		return yomigana;
	}
	public void setYomigana(String yomigana) {
		this.yomigana = yomigana;
	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

package yurufuwa.prog.sample;

public class Pref {

private String kenCode = null;

private String kenName = null;

private String yomigana = null;

public String getKenCode() {

return kenCode;

}

public void setKenCode(String kenCode) {

this.kenCode = kenCode;

}

public String getKenName() {

return kenName;

}

public void setKenName(String kenName) {

this.kenName = kenName;

}

public String getYomigana() {

return yomigana;

}

public void setYomigana(String yomigana) {

this.yomigana = yomigana;

}

package yurufuwa.prog.sample;

import java.util.List;

public class PrefList {

	List<Pref> prefList = null;

	public List<Pref> getPrefList() {
		return prefList;
	}

	public void setPrefList(List<Pref> prefList) {
		this.prefList = prefList;
	}
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

package yurufuwa.prog.sample;

import java.util.List;

public class PrefList {

List<Pref> prefList = null;

public List<Pref> getPrefList() {

return prefList;

}

public void setPrefList(List<Pref> prefList) {

this.prefList = prefList;

}

{
	"prefList" : [
		{
			"kenCode" : "01",
			"kenName" : "北海道",
			"yomigana" : "ほっかいどう"
		},
		{
			"kenCode" : "02",
			"kenName" : "青森県",
			"yomigana" : "あおもりけん"
		},
		{
			"kenCode" : "03",
			"kenName" : "岩手県",
			"yomigana" : "いわてけん"
		}
	]
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

{

"prefList" : [

{

"kenCode" : "01",

"kenName" : "北海道",

"yomigana" : "ほっかいどう"

},

{

"kenCode" : "02",

"kenName" : "青森県",

"yomigana" : "あおもりけん"

},

{

"kenCode" : "03",

"kenName" : "岩手県",

"yomigana" : "いわてけん"

}

]

}

【Java】JSONの扱い(1) – ファイルを読み込んでオブジェクトに変換

解説動画

ABOUTこの記事をかいた人

NEW POSTこのライターの最新記事

Youtube版【中級編Java(25)】データベースアプリケーションの作成…

Java DateTimeFormatterを使って、LocalDateTi…

【Java】JSONの扱い(2) - ブラウザとJSONのデータを受け渡しす…

Youtube版【中級編Java(24)】データベースアプリケーションの作成…

サイト内検索

カテゴリー

解説動画

RECOMMENDこちらの記事も人気です。

Youtube版【初めてみようJava(45)】スタティック変数―値の共…

Youtube版【初めてみようJava(41)】キャスト(2)

【Java】Apache POIを使って、Wordのファイルを読み取る-…

Youtube版【初めてみようJava(6)】if文を使った条件分岐―パ…

Youtube版【Java】画像ファイルを読み書きする Buffered…

Youtube版【中級編Java(16)】Webアプリケーションの作成(…

Youtube版【Java】ファイルのコピー、移動、削除-Filesクラ…

Youtube版【初めてみようJava(11)】for文を使った繰り返し…

ABOUTこの記事をかいた人

NEW POSTこのライターの最新記事

Youtube版【中級編Java(25)】データベースアプリケーションの作成…

Java DateTimeFormatterを使って、LocalDateTi…

【Java】JSONの扱い(2) - ブラウザとJSONのデータを受け渡しす…

Youtube版【中級編Java(24)】データベースアプリケーションの作成…

サイト内検索

カテゴリー

タグ