Jackson使用示例-Bean、XML、Json之间相互转换

<!--注解包，提供标准注解功能-->
<dependency>
	<groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
</dependency>
<!--核心包，提供基于"流模式"解析的相关 API-->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
</dependency>
<!--数据绑定包，提供基于"对象绑定" 解析的相关 API （ ObjectMapper ） 和"树模型" 解析的相关 API-->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
</dependency>
<!--日期类型序列化包-->
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>
<!--引入xml功能-->
<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
</dependency>

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Employees {
    private String name;
    private Integer age;
    private String sex;
}

/**
 * @author 秋一叶
 * @create 2024-04-23 21:00
 * json字符串和对象、集合、map互转
 *
 */
public class Demo2 {
    public static void main(String[] args) {
   		ObjectMapper objectMapper = new ObjectMapper();
        Employees employees1 = new Employees("秋一叶",18,"男");
        Employees employees2 = new Employees("小王",20,"男");
        
        try {
            //对象转json字符串
            String jsonString = objectMapper.writeValueAsString(employees1);
            //json字符串转为对象
            Employees emp1 = objectMapper.readValue(jsonString, Employees.class);
            System.out.println("json字符串：" + jsonString);
            System.out.println("对象1：" + emp1);

            System.out.println("====================================================");

            //对象转为json字符串写入文件
            objectMapper.writeValue(new File("emp.json"), employees1);
            //从文件中读取json字符串转为对象
            Employees emp2 = objectMapper.readValue(new File("emp.json"), Employees.class);
            System.out.println("对象2：" + emp2);

            System.out.println("====================================================");

            //对象写为字节流
            byte[] bytes = objectMapper.writeValueAsBytes(employees1);
            //字节流转为对象
            Employees emp3 = objectMapper.readValue(bytes, Employees.class);
            System.out.println("对象3：" + emp3);

            System.out.println();
            System.out.println("*****************************************************");
            System.out.println();


            //Map和json互转
            Map<String, Object> map = Maps.newHashMap();
            map.put("001", employees1);
            map.put("002", "元旦");
            String mapToString = objectMapper.writeValueAsString(map);
            Map<String, Object> stringToMap = objectMapper.readValue(mapToString, new TypeReference<Map<String, Object>>() {
            });
            System.out.println("json字符串：" + mapToString);
            System.out.println("map：" + stringToMap);

            System.out.println("====================================================");

            //List和json互转
            List<Employees> empList = Lists.newArrayList(employees1, employees2);
            String jsonList = objectMapper.writeValueAsString(empList);
            List<Employees> stringToList = objectMapper.readValue(jsonList, new TypeReference<List<Employees>>() {
            });
            System.out.println("json字符串：" + jsonList);
            System.out.println("map：" + stringToList);

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

json字符串：{"name":"秋一叶","age":18,"sex":"男"}
对象1：Employees(name=秋一叶, age=18, sex=男)
====================================================
对象2：Employees(name=秋一叶, age=18, sex=男)
====================================================
对象3：Employees(name=秋一叶, age=18, sex=男)

*****************************************************

json字符串：{"001":{"name":"秋一叶","age":18,"sex":"男"},"002":"元旦"}
map：{001={name=秋一叶, age=18, sex=男}, 002=元旦}
====================================================
json字符串：[{"name":"秋一叶","age":18,"sex":"男"},{"name":"小王","age":20,"sex":"男"}]
map：[Employees(name=秋一叶, age=18, sex=男), Employees(name=小王, age=20, sex=男)]

@Data
@JacksonXmlRootElement(localName = "RootName")
public class Department {
    @JacksonXmlProperty(localName = "DepName")
    private String depName;
    
    @JacksonXmlElementWrapper(localName = "EmpMessage")
    @JacksonXmlProperty(localName = "EmpName")
    List<Employees> employees; 
}

public class Demo1 {
    public static void main(String[] args) {
        XmlMapper xmlMapper = new XmlMapper();
        //字段为null，自动忽略，不再序列化
        xmlMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

        Department department = new Department();
        Employees employees1 = new Employees("秋一叶",18,"男");
        Employees employees2 = new Employees("小王",20,"男");
        department.setDepName("产品研发部门");
        department.setEmployees(Lists.newArrayList(employees1, employees2));

        try {
            //对象转xml
            String xml = xmlMapper.writeValueAsString(department);
            //xml转对象
            Department dep = xmlMapper.readValue(xml, Department.class);

            System.out.println("返回的xml：" + xml);
            System.out.println("返回的实体：" + dep);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }
}

返回的xml：<RootName><DepName>产品研发部门</DepName><EmpMessage><EmpName><name>秋一叶</name><age>18</age><sex>男</sex></EmpName><EmpName><name>小王</name><age>20</age><sex>男</sex></EmpName></EmpMessage></RootName>
返回的实体：Department(depName=产品研发部门, employees=[Employees(name=秋一叶, age=18, sex=男), Employees(name=小王, age=20, sex=男)])