Jackson 工具类

Jackson 工具类

示例代码中包含 Date LocalDate LocalDateTime 类型处理方式
JavaBean 与 json 相互转换 bean2json json2bean
List 与 json 相互转换 list2json json2list
Map 与 json 相互转换map2json json2map

pom.xml

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>
    <groupId>com.lihaohzegroupId>
    <artifactId>chap06artifactId>
    <version>1.0.0version>
    <packaging>jarpackaging>
    <name>chap06name>
    <url>https://mvnrepository.com/url>

    <properties>
        
        <maven.compiler.source>21maven.compiler.source>
        <maven.compiler.target>21maven.compiler.target>
        <maven.compiler.compilerVersion>21maven.compiler.compilerVersion>
        <maven.compiler.encoding>utf-8maven.compiler.encoding>
        <project.build.sourceEncoding>utf-8project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
        <maven.test.failure.ignore>truemaven.test.failure.ignore>
        <maven.test.skip>truemaven.test.skip>

        <commons-io.version>2.14.0commons-io.version>
        <commons-lang3.version>3.13.0commons-lang3.version>
        <hutool.version>5.8.22hutool.version>
        <jackson.version>2.15.3jackson.version>
        <junit.version>5.10.0junit.version>
        <lombok.version>1.18.30lombok.version>
    properties>

    <dependencies>
        
        <dependency>
            <groupId>org.junit.jupitergroupId>
            <artifactId>junit-jupiter-apiartifactId>
            <version>${junit.version}version>
            
            <scope>testscope>
        dependency>
        
        <dependency>
            <groupId>org.junit.jupitergroupId>
            <artifactId>junit-jupiter-engineartifactId>
            <version>${junit.version}version>
            <scope>testscope>
        dependency>
        
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <version>${lombok.version}version>
            <scope>providedscope>
        dependency>
        
        <dependency>
            <groupId>cn.hutoolgroupId>
            <artifactId>hutool-allartifactId>
            <version>${hutool.version}version>
        dependency>
        
        <dependency>
            <groupId>org.apache.commonsgroupId>
            <artifactId>commons-lang3artifactId>
            <version>${commons-lang3.version}version>
        dependency>
        
        <dependency>
            <groupId>commons-iogroupId>
            <artifactId>commons-ioartifactId>
            <version>${commons-io.version}version>
        dependency>
        
        <dependency>
            <groupId>com.fasterxml.jackson.coregroupId>
            <artifactId>jackson-coreartifactId>
            <version>${jackson.version}version>
        dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.coregroupId>
            <artifactId>jackson-annotationsartifactId>
            <version>${jackson.version}version>
        dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.coregroupId>
            <artifactId>jackson-databindartifactId>
            <version>${jackson.version}version>
        dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.datatypegroupId>
            <artifactId>jackson-datatype-jsr310artifactId>
            <version>${jackson.version}version>
        dependency>
    dependencies>
project>

Jackson 工具类

package com.lihaozhe.util.json.jackson;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.MapType;

import java.util.List;
import java.util.Map;

/**
 * @author 李昊哲
 * @version 1.0
 * @create 2023/10/19
 */
public class JacksonUtils {
    /**
     * 实例化 ObjectMapper
     */
    private final static ObjectMapper objectMapper = new ObjectMapper();

    /**
     * 将对象转换成json字符串。
     * 
Title: pojoToJson
     * 
Description: 
     *
     * @param bean JavaBean对象
     * @return json格式字符串
     */
    public static String bean2json(Object bean) {
        try {
            return objectMapper.writeValueAsString(bean);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            return null;
        }
    }


    /**
     * 将json结果集转化为对象
     *
     * @param jsonString json格式字符串
     * @param beanType   对象类型
     * @return JavaBean对象
     */
    public static <T> T json2bean(String jsonString, Class<T> beanType) {
        try {
            return objectMapper.readValue(jsonString, beanType);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 将json数据转换成pojo对象list
     * 
Title: jsonToList
     * 
Description: 
     *
     * @param jsonString json格式字符串
     * @param beanType   对象类型
     * @return List对象
     */
    public static <T> List<T> json2list(String jsonString, Class<T> beanType) {
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(List.class, beanType);
        try {
            return objectMapper.readValue(jsonString, javaType);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 将json数据转换成pojo对象list
     * 
Title: jsonToList
     * 
Description: 
     *
     * @param jsonString json格式字符串
     * @param keyType    key对象类型
     * @param valueType  value对象类型
     * @return List对象
     */
    public static <K, V> Map<K, V> json2map(String jsonString, Class<K> keyType, Class<V> valueType) {
        MapType mapType = objectMapper.getTypeFactory().constructMapType(Map.class, keyType, valueType);
        try {
            return objectMapper.readValue(jsonString, mapType);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}

javabean与json格式字符串相互转换

准备javabean

package com.lihaozhe.json.jackson;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.databind.deser.std.DateDeserializers;
import com.fasterxml.jackson.databind.ser.std.DateSerializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.lihaozhe.util.date.DateUtils;
import lombok.*;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.Date;

/**
 * @author 李昊哲
 * @version 1.0
 * @create 2023/10/19
 */
@Getter
@Setter
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class Emp {
    /**
     * 账号
     */
    private String account;
    /**
     * 密码
     */
    private String password;
    /**
     * 姓名
     */
    private String name;
    /**
     * 性别 1 代表男性 0 代表女性
     */
    private int gender;

    /**
     * 入职时间
     */
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH-mm-ss", locale = "zh", timezone = "GMT+8")
    @JsonSerialize(using = DateSerializer.class)
    @JsonDeserialize(using = DateDeserializers.DateDeserializer.class)
    private Date hiredate;
    /**
     * 离职日期
     */
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH-mm-ss", locale = "zh", timezone = "GMT+8")
    @JsonSerialize(using = DateSerializer.class)
    @JsonDeserialize(using = DateDeserializers.DateDeserializer.class)
    private Date turnoverDate;
    /**
     * 日期
     */
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd", locale = "zh", timezone = "GMT+8")
    @JsonSerialize(using = LocalDateSerializer.class)
    @JsonDeserialize(using = LocalDateDeserializer.class)
    private LocalDate createDate;
    /**
     * 账号停用时间
     */
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH-mm-ss", locale = "zh", timezone = "GMT+8")
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    private LocalDateTime createDateTime;

    public Emp(String account, String password, String name, int gender) {
        this.account = account;
        this.password = password;
        this.name = name;
        this.gender = gender;
        this.hiredate = new Date();
        this.createDate = LocalDate.now();
        this.createDateTime = LocalDateTime.now();
    }
}

javabean转json格式字符串

Emp emp = new Emp("root", "e10adc3949ba59abbe56e057f20f883e", "李昊哲", 1);
System.out.println(emp);
String json = JacksonUtils.bean2json(emp);
System.out.println(json);
    

结果如下：

Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 19:58:06 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:58:06.343)
{"account":"root","password":"e10adc3949ba59abbe56e057f20f883e","name":"李昊哲","gender":1,"hiredate":"2023-10-19 19-58-06","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 19-58-06"}

json格式字符串转javabean

Emp emp = new Emp("root", "e10adc3949ba59abbe56e057f20f883e", "李昊哲", 1);
System.out.println(emp);
String json = JacksonUtils.bean2json(emp);
System.out.println(json);

结果如下：

Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 19:58:06 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:58:06.343)
{"account":"root","password":"e10adc3949ba59abbe56e057f20f883e","name":"李昊哲","gender":1,"hiredate":"2023-10-19 19-58-06","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 19-58-06"}
Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 19:58:06 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:58:06.343)

list与json格式字符串相互转换

list转json格式字符串

List<Emp> empList = new ArrayList<>();
empList.add(new Emp("root", "e10adc3949ba59abbe56e057f20f883e", "李昊哲", 1));
empList.add(new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "李哲", 0));
empList.forEach(System.out::println);
String json = JacksonUtils.bean2json(empList);
System.out.println(json);

结果如下：

Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 19:59:09 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:59:09.321)
Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李哲, gender=0, hiredate=Thu Oct 19 19:59:09 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:59:09.323)
[{"account":"root","password":"e10adc3949ba59abbe56e057f20f883e","name":"李昊哲","gender":1,"hiredate":"2023-10-19 19-59-09","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 19-59-09"},{"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"李哲","gender":0,"hiredate":"2023-10-19 19-59-09","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 19-59-09"}]

json格式字符串转list

List<Emp> empList = new ArrayList<>();
empList.add(new Emp("root", "e10adc3949ba59abbe56e057f20f883e", "李昊哲", 1));
empList.add(new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "李哲", 0));
empList.forEach(System.out::println);
String json = JacksonUtils.bean2json(empList);
System.out.println(json);
// JavaType javaType = objectMapper.getTypeFactory().constructParametricType(List.class, Emp.class);
// List emps = objectMapper.readValue(json, javaType);
List<Emp> emps = objectMapper.readValue(json, new TypeReference<List<Emp>>() {
        });
emps.forEach(System.out::println);

结果如下：

Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 19:59:09 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:59:09.321)
Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李哲, gender=0, hiredate=Thu Oct 19 19:59:09 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:59:09.323)
[{"account":"root","password":"e10adc3949ba59abbe56e057f20f883e","name":"李昊哲","gender":1,"hiredate":"2023-10-19 19-59-09","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 19-59-09"},{"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"李哲","gender":0,"hiredate":"2023-10-19 19-59-09","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 19-59-09"}]
Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 19:59:09 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:59:09.321)
Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李哲, gender=0, hiredate=Thu Oct 19 19:59:09 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19:59:09.323)

map与json格式字符串相互转换

map转json格式字符串

Map<String, Emp> map = new HashMap<>();
map.put("root", new Emp("root", "e10adc3949ba59abbe56e057f20f883e", "李昊哲", 1));
map.put("admin", new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "李哲", 0));
map.forEach((key, value) -> System.out.println("key >>> " + key + "\tvalue >>> " + value));
String json = JacksonUtils.bean2json(map);
System.out.println(json);

结果如下：

key >>> root	value >>> Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 20:01:52 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T20:01:52.568)
key >>> admin	value >>> Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李哲, gender=0, hiredate=Thu Oct 19 20:01:52 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T20:01:52.570)
{"root":{"account":"root","password":"e10adc3949ba59abbe56e057f20f883e","name":"李昊哲","gender":1,"hiredate":"2023-10-19 20-01-52","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 20-01-52"},"admin":{"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"李哲","gender":0,"hiredate":"2023-10-19 20-01-52","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 20-01-52"}}

json格式字符串转map

Map<String, Emp> map = new HashMap<>();
map.put("root", new Emp("root", "e10adc3949ba59abbe56e057f20f883e", "李昊哲", 1));
map.put("admin", new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "李哲", 0));
map.forEach((key, value) -> System.out.println("key >>> " + key + "\tvalue >>> " + value));
String json = JacksonUtils.bean2json(map);
System.out.println(json);
// MapType mapType = objectMapper.getTypeFactory().constructMapType(Map.class, String.class, Emp.class);
// Map empMap = objectMapper.readValue(json, mapType);
Map<String, Emp> empMap = objectMapper.readValue(json, new TypeReference<Map<String, Emp>>() {
});
empMap.forEach((key, value) -> System.out.println("key >>> " + key + "\tvalue >>> " + value));

结果如下：

key >>> root	value >>> Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 20:01:52 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T20:01:52.568)
key >>> admin	value >>> Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李哲, gender=0, hiredate=Thu Oct 19 20:01:52 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T20:01:52.570)
{"root":{"account":"root","password":"e10adc3949ba59abbe56e057f20f883e","name":"李昊哲","gender":1,"hiredate":"2023-10-19 20-01-52","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 20-01-52"},"admin":{"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"李哲","gender":0,"hiredate":"2023-10-19 20-01-52","turnoverDate":null,"createDate":"2023-10-19","createDateTime":"2023-10-19 20-01-52"}}
key >>> root	value >>> Emp(account=root, password=e10adc3949ba59abbe56e057f20f883e, name=李昊哲, gender=1, hiredate=Thu Oct 19 20:01:52 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T20:01:52.568)
key >>> admin	value >>> Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李哲, gender=0, hiredate=Thu Oct 19 20:01:52 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T20:01:52.570)