1、先看用法,代码跑起来自然就入门了。
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.11.0</version>
</dependency>
Person.java
public class Person {
private int age;
private String name;
private String school;
private String major;
public Person() {
}
public Person(int age, String name, String school, String major) {
this.age = age;
this.name = name;
this.school = school;
this.major = major;
}
public void setAge(int age) {
this.age = age;
}
public void setName(String name) {
this.name = name;
}
public void setSchool(String school) {
this.school = school;
}
public void setMajor(String major) {
this.major = major;
}
public int getAge() {
return age;
}
public String getName() {
return name;
}
public String getSchool() {
return school;
}
public String getMajor() {
return major;
}
}
public class JacksonDemo {
public static void Serialize() throws IOException {
//使用ObjectMapper来转化对象json
ObjectMapper mapper = new ObjectMapper();
Person person = new Person(23,"张三","天津大学","光学工程");
mapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
//设置序列化后的格式,INDENT_OUTPUT表示缩进输出,true表示试该配置生效
mapper.configure(SerializationFeature.INDENT_OUTPUT,true);
//序列化结果输出为字符串
String str = mapper.writeValueAsString(person);
System.out.println(str);
//序列化结果输出为文件输出
mapper.writeValue(new File("Jackson.json"),person);
}
public static void main(String[] args) throws IOException {
Serialize();
}
}
注释mapper.configure一行输出:
//mapper.configure(SerializationFeature.INDENT_OUTPUT,true);
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.5</version>
</dependency>
这里还不会怎么直接写入json文件,直接找了字符串写入json文件的写法:
public class GsonDemo {
public static void saveJson(String jsonStr, String fileName){
/**
* 将String类型写入到 *.json中
*/
FileWriter writer;
try{
writer = new FileWriter(fileName);
writer.write(jsonStr);
writer.flush();
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static String readJson(String fileName){
/**
* @param filename 读取 *.json文件
*/
StringBuffer content = new StringBuffer();
BufferedReader reader = null;
try{
reader = new BufferedReader(new FileReader(fileName));
String line = null;
while ((line=reader.readLine())!=null){
content.append(line);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
try{
if(reader!=null){
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return content.toString();
}
/**
* 序列化
*/
public static void Serial(){
String fileName = "gson.json";
Person person = new Person(23,"张三","天津大学","光学工程");
String str = new Gson().toJson(person);
//将对象进行实例化
String jsonStr = new Gson().toJson(person);
//保存json文件
saveJson(jsonStr,fileName);
System.out.println("序列化结果:"+jsonStr);
}
/**
* 反序列化
*/
public static void deSerial(){
String fileName = "gson.json";
//读取json文件
String jsonStr = readJson(fileName);
//将对象反序列化
Person person1DeSerial = new Gson().fromJson(jsonStr,Person.class);
System.out.println("反序列化结果:"+person1DeSerial);
}
public static void main(String[] args) {
Serial();
//等待一会
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
deSerial();
}
}
在deSerial()方法中直接输出反序列化后的结果,需要重写toString()方法,使用apache.commoms重写的,在pom中加入:
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.1</version>
</dependency>
最后输出:
希望这套代码能帮助到像我一样刚入门的你(*^_^*)
本文地址:https://blog.csdn.net/Li_haiyu/article/details/107477810
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