[Jackson] ObjectMapper, String to Map, to List, Object to JSON

https://hermeslog.tistory.com/710

[ModelMapper] Object to Object 변환

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Object를 Map으로 변경

Json 데이터를 Map으로 변경

Json 데이터를 List로 변경

Object를 Json으로 변경

package test.json;

import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonSample {
    
    private static Logger logger = LoggerFactory.getLogger( JacksonSample.class );
    
    public static void main( String ... args ) {
        
        Map<String, Object> rMap = convJsonToMap( getSampleMap() );
        logger.debug( "result :: {}", rMap );
        
        List<Object> rList = convJsonToList( getSampleList() );
        logger.debug( "result :: {}", rList );
        
        String json = convObjectToJson( getObjectList() );
        logger.debug( "result :: {}", json );
        
        toBeauty( getObjectList() );
    }
    
    /**
     * Json String -> Map
     * 
     * @param dto
     * @return
     */
    public static Map<String, Object> convJsonToMap( String json ) {
        ObjectMapper        objectMapper = new ObjectMapper();
        
        Map<String, Object> map          = null;
        try {
            map = objectMapper.readValue( json, new TypeReference<Map<String, Object>>() {} );
        } catch ( IOException e ) {
            throw new RuntimeException( e );
        }
        
        return map;
    }
    
    /**
     * Json String -> List
     * 
     * @param dto
     * @return
     */
    public static List<Object> convJsonToList( String json ) {
        ObjectMapper objectMapper = new ObjectMapper();
        
        List<Object> list         = null;
        try {
            list = objectMapper.readValue( json, new TypeReference<List<Object>>() {} );
        } catch ( IOException e ) {
            throw new RuntimeException( e );
        }
        
        return list;
    }

    /**
     * Object -> Json String
     * 
     * @param dto
     * @return
     */
    public static String convObjectToJson( Object dto ) {
        ObjectMapper objectMapper = new ObjectMapper();
        
        String       body         = null;
        try {
            body = objectMapper.writeValueAsString( dto );
        } catch ( IOException e ) {
            throw new RuntimeException( e );
        }
        
        return body;
    }
    
    /**
     * Object -> Json String 예쁘게 찍기
     * 
     * @param dto
     * @return
     */
    public static void toBeauty( Object json ) {
        ObjectMapper objectMapper = new ObjectMapper();
        
        String       jStr         = null;
        try {
            jStr = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString( json );
        } catch ( JsonProcessingException e ) {
            throw new RuntimeException( e );
        }
        
        logger.debug( "{}", jStr );
    }
    
    
    public static String getSampleMap() {
        StringBuffer jMap = new StringBuffer();
        jMap.append( "{ \"ID\": \"4\", \"USERNAME\":\"aa\", \"PASSWORD\": \"aa\", \"ROLE_ID\": \"1\", \"STATUS\": \"D\" }" );
        
        return jMap.toString();
    }
    
    public static String getSampleList() {
        StringBuffer jList = new StringBuffer();
        jList.append( "[" );
        jList.append( "{ \"ID\": \"4\", \"USERNAME\":\"aa\", \"PASSWORD\": \"aa\", \"ROLE_ID\": \"1\", \"STATUS\": \"D\" }," );
        jList.append( "{ \"ID\": \"5\", \"USERNAME\":\"bb\", \"PASSWORD\": \"bb\", \"ROLE_ID\": \"2\", \"STATUS\": \"D\" }," );
        jList.append( "{ \"ID\": \"6\", \"USERNAME\":\"cc\", \"PASSWORD\": \"cc\", \"ROLE_ID\": \"3\", \"STATUS\": \"D\" }" );
        jList.append( "]" );
        
        return jList.toString();
    }
    
    public static List<Object> getObjectList() {
        List<Object> list = new ArrayList<>();
        list.add( new User( "4", "한글", "aa", "1", "D" ) );
        list.add( new User( "5", "bb", "bb", "2", "D" ) );
        list.add( new User( "6", "cc", "cc", "3", "D" ) );
        
        return list;
    }
}

class User implements Serializable {
    
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    
    public User( String id, String password ) {
        this.id       = id;
        this.password = password;
    }
    
    public User( String id, String username, String password, String roleId, String status ) {
        this.id       = id;
        this.password = password;
        this.username = username;
        this.roleId   = roleId;
        this.status   = status;
    }
    
    private String id;
    private String password;
    private String username;
    private String roleId;
    private String status;

    
    public String getId() {
        return id;
    }

    
    public void setId( String id ) {
        this.id = id;
    }

    
    public String getPassword() {
        return password;
    }

    
    public void setPassword( String password ) {
        this.password = password;
    }

    
    public String getUsername() {
        return username;
    }

    
    public void setUsername( String username ) {
        this.username = username;
    }

    
    public String getRoleId() {
        return roleId;
    }

    
    public void setRoleId( String roleId ) {
        this.roleId = roleId;
    }

    
    public String getStatus() {
        return status;
    }

    
    public void setStatus( String status ) {
        this.status = status;
    }
    
}

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DEBUG: test.json.JacksonSample - result :: {ID=4, USERNAME=aa, PASSWORD=aa, ROLE_ID=1, STATUS=D}
DEBUG: test.json.JacksonSample - result :: [{ID=4, USERNAME=aa, PASSWORD=aa, ROLE_ID=1, STATUS=D}, {ID=5, USERNAME=bb, PASSWORD=bb, ROLE_ID=2, STATUS=D}, {ID=6, USERNAME=cc, PASSWORD=cc, ROLE_ID=3, STATUS=D}]
DEBUG: test.json.JacksonSample - result :: [{"id":"4","password":"aa","username":"한글","roleId":"1","status":"D"},{"id":"5","password":"bb","username":"bb","roleId":"2","status":"D"},{"id":"6","password":"cc","username":"cc","roleId":"3","status":"D"}]
DEBUG: test.json.JacksonSample - [ {
"id" : "4",
"password" : "aa",
"username" : "한글",
"roleId" : "1",
"status" : "D"
}, {
"id" : "5",
"password" : "bb",
"username" : "bb",
"roleId" : "2",
"status" : "D"
}, {
"id" : "6",
"password" : "cc",
"username" : "cc",
"roleId" : "3",
"status" : "D"
} ]

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package test.mapper;

import java.io.Serializable;
import java.util.Map;

import com.fasterxml.jackson.databind.ObjectMapper;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.ToString;

public class ObjectMapperSample {
    
    public static void main(String... args) {
        ObjectMapper   objectMapper = new ObjectMapper();
        BoardSearchDto dto          = BoardSearchDto.builder()
                .keyword("keyword")
                .searchType("searchType")
                .page(1)
                .recordSize(10)
                .pageSize(10)
                .build();
        
        Map<String, Object> map = objectMapper.convertValue(dto, Map.class);
        
        System.out.println("map :: " + map);
        
        BoardSearchDto board = objectMapper.convertValue(map, BoardSearchDto.class);
        
        // [실행 결과]
        System.out.println("board :: " + board);
    }
}

@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@ToString
class BoardSearchDto {
    private static final long serialVersionUID = 1L;
    
    private int    page;       // 현재 페이지 번호
    private int    recordSize; // 페이지당 출력할 데이터 개수
    private int    pageSize;   // 화면 하단에 출력할 페이지 사이즈
    private String keyword;    // 검색 키워드
    private String searchType; // 검색 유형
}

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map :: {page=1, recordSize=10, pageSize=10, keyword=keyword, searchType=searchType}
board :: BoardSearchDto(page=1, recordSize=10, pageSize=10, keyword=keyword, searchType=searchType)

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https://hermeslog.tistory.com/710

[ModelMapper] Object to Object 변환