- jackson 作用 ?
可以将 javabean 转换成 json/xml, 也可以将 json/xml 转换成 javabean jackson 如何使用？
主要是通过 ObjectMapper 和 XmlMapper 实现转换-
@JsonInclude(JsonInclude.Include.NON_NULL) private DeviceInfo deviceInfo; null bean对象转为xml string时不转换 或者
mapper.setSerializationInclusion(Include.NON_NULL); null不转换
jackson 导包如下：
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.5</version> </dependency> <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>2.9.5</version> </dependency> <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>2.9.5</version> </dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.dataformat/jackson-dataformat-xml --> <dependency> <groupId>com.fasterxml.jackson.dataformat</groupId> <artifactId>jackson-dataformat-xml</artifactId> <version>2.9.5</version> </dependency>
Person实体类如下
package com.ps.ukefu.entcunsomer;
/**
* Created by Admin on 2018/6/11.
*/
import java.util.Arrays;
import java.util.List;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
@JacksonXmlRootElement(localName="person")
public class Person {
private String name;
private Integer age;
private String sex;
private String telephone;
@JacksonXmlProperty(isAttribute = true)
private String attribute;
// @JacksonXmlElementWrapper(localName = "friends",useWrapping = false)
//生成 <?xml version='1.0' encoding='UTF-8'?><person attribute="post"><name>sarah</name><age>10</age><sex>male</sex><telephone>12345678</telephone><friend>mattew</friend><friend>phoenix</friend></person>
@JacksonXmlElementWrapper(localName = "friends",useWrapping = true)
//生成 <?xml version='1.0' encoding='UTF-8'?><person attribute="post"><name>sarah</name><age>10</age><sex>male</sex><telephone>12345678</telephone><friends><friend>mattew</friend><friend>phoenix</friend></friends></person>
@JacksonXmlProperty(localName = "friend")
private List<String> friends;
/**
* @return the name
*/
public String getName() {
return name;
}
/**
* @param name the name to set
*/
public void setName(String name) {
this.name = name;
}
/**
* @return the age
*/
public Integer getAge() {
return age;
}
/**
* @param age the age to set
*/
public void setAge(Integer age) {
this.age = age;
}
/**
* @return the sex
*/
public String getSex() {
return sex;
}
/**
* @param sex the sex to set
*/
public void setSex(String sex) {
this.sex = sex;
}
/**
* @return the telephone
*/
public String getTelephone() {
return telephone;
}
/**
* @param telephone the telephone to set
*/
public void setTelephone(String telephone) {
this.telephone = telephone;
}
/**
* @return the friends
*/
public List<String> getFriends() {
return friends;
}
/**
* @param friends the friends to set
*/
public void setFriends(List<String> friends) {
this.friends = friends;
}
/**
* @param name
* @param age
* @param sex
* @param telephone
* @param friends
*/
public Person(String name, Integer age, String sex, String telephone, List<String> friends) {
super();
this.name = name;
this.age = age;
this.sex = sex;
this.telephone = telephone;
this.friends = friends;
}
public String getAttribute() {
return attribute;
}
public void setAttribute(String attribute) {
this.attribute = attribute;
}
/**
*
*/
public Person() {
super();
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + ", sex=" + sex + ", telephone=" + telephone + ", friends="
+ Arrays.toString(friends.toArray()) + "]";
}
}
- 具体测试代码如下：
package com.ps.ukefu.entcunsomer;
/**
* Author:ZhuShangJin
* Date:2018/6/11
*/
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import com.fasterxml.jackson.dataformat.xml.ser.ToXmlGenerator;
import org.junit.Before;
import org.junit.Test;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
public class TestJackson {
/**
* convert json to javabean or javabean to json.
*/
private ObjectMapper objectMapper = new ObjectMapper();
/**
* convert xml to javabean or javabean to xml.
*/
private XmlMapper xmlMapper = new XmlMapper();
private Person person;
@Before
public void init(){
person = new Person();
person.setName("sarah");
person.setAge(10);
person.setSex("male");
person.setTelephone("12345678");
person.setAttribute("post");
List<String> friends = new ArrayList<String>();
friends.add("mattew");
friends.add("phoenix");
// String[] friends = new String[2];
// friends[0] = "mattew";
// friends[1] = "phoenix";
person.setFriends(friends);
}
/**
* convert java bean to json.
* @throws IOException
*/
@Test
public void testJavabeanToJSON() throws IOException{
// java bean to json
String json = objectMapper.writeValueAsString(person);
System.out.println("json:" + json);
// json:{"name":"sarah","age":10,"sex":"male","telephone":"12345678","attribute":"post","friends":["mattew","phoenix"]}
}
/**
* convert json to java bean.
* @throws JsonParseException
* @throws JsonMappingException
* @throws IOException
*/
@Test
public void testJsonToJavabean() throws JsonParseException, JsonMappingException, IOException{
String json = "{\"name\":\"sarah\",\"age\":10,\"sex\":\"male\",\"telephone\":\"12345678\",\"friends\":[\"mattew\",\"phoenix\"]}";
// json to java bean
Person person = objectMapper.readValue(json, Person.class);
System.out.println("person:" + person);
// person:Person [name=sarah, age=10, sex=male, telephone=12345678, friends={mattew, phoenix}]
}
/**
* convert xml to javabean.
* @throws JsonParseException
* @throws JsonMappingException
* @throws IOException
*/
@Test
public void testXmlToJavabean() throws JsonParseException, JsonMappingException, IOException{
XmlMapper xmlmapper = new XmlMapper();
xmlmapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
// java bean to xml
String xml = xmlmapper.writeValueAsString(person);
System.out.println("xml:" + xml);
// xml:<?xml version='1.0' encoding='UTF-8'?><person attribute="post"><name>sarah</name><age>10</age><sex>male</sex><telephone>12345678</telephone><friends><friend>mattew</friend><friend>phoenix</friend></friends></person>
// xml to java bean
Person generatePerson = xmlMapper.readValue(xml, Person.class);
System.out.println("person:" + generatePerson.toString());
// person:Person [name=sarah, age=10, sex=male, telephone=12345678, friends={mattew, phoenix}]
}
/**
* convert javabean to xml.
* @throws IOException
*/
@Test
public void testJavabeanToXml() throws IOException{
//添加 xml头部
xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
// java bean to xml
String xml = xmlMapper.writeValueAsString(person);
System.out.println("xml:" + xml);
// xxml:<?xml version='1.0' encoding='UTF-8'?><person attribute="post"><name>sarah</name><age>10</age><sex>male</sex><telephone>12345678</telephone><friends><friend>mattew</friend><friend>phoenix</friend></friends></person>
}
/**
* convert map to json.
* @throws JsonProcessingException
*/
@Test
public void testMapToJSON() throws JsonProcessingException{
Map<String, Object> map = new HashMap<String, Object>();
map.put("name", "sarah");
map.put("age", 10);
// map to json
String json = objectMapper.writeValueAsString(map);
System.out.println("json:" + json);
// json:{"friends":["mattew","phoenix"],"age":10,"name":"sarah"}
}
/**
* convert json to map.
* @throws JsonParseException
* @throws JsonMappingException
* @throws IOException
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
@Test
public void testJsonToMap() throws JsonParseException, JsonMappingException, IOException{
String json = "{\"friends\":[\"mattew\",\"phoenix\"],\"age\":10,\"name\":\"sarah\"}";
// json to map
Map map = objectMapper.readValue(json, HashMap.class);
Iterator<Entry<String, Object>> iterator = map.entrySet().iterator();
while(iterator.hasNext()){
Entry<String, Object> entry = (Entry<String, Object>)iterator.next();
System.out.print(entry.getKey() + ":" + entry.getValue() + ", ");
// friends:[mattew, phoenix], name:sarah, age:10,
}
}
}