Jackson详解

一 jackson对象和字符串及其数组对象和字符串相互转换

1.maven引入Jackson包

<dependencies>
    <dependency>
        <groupId>com.fasterxml.jackson.coregroupId>
        <artifactId>jackson-coreartifactId>
        <version>2.7.4version>
    dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.coregroupId>
        <artifactId>jackson-annotationsartifactId>
        <version>2.7.4version>
    dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.coregroupId>
        <artifactId>jackson-databindartifactId>
        <version>2.7.4version>
    dependency>
dependencies>

2.新建User类

import java.util.Date;

public class User {
    private String mName;
    private int age;
    private Date birthday;
    private String email;

    public String getmName() {
        return mName;
    }

    public void setmName(String mName) {
        this.mName = mName;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User [mName=" + mName + ", age=" + age + ", birthday="
                + birthday + ", email=" + email + "]";
    }

}

3.新建测试类

public class JacksonTest {
    public static void main(String[] args) throws IOException {
        User user=new User();
        user.setAge(11);
        user.setBirthday(new Date());
        user.setEmail("123456");
        user.setmName("jesse1");

        ObjectMapper mapper = new ObjectMapper();
        //当反序列化json时，未知属性会引起的反序列化被打断，这里我们禁用未知属性打断反序列化功能，  
        //因为，例如json里有10个属性，而我们的bean中只定义了2个属性，其它8个属性将被忽略  
        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        // Convert object to JSON string
        String json = mapper.writeValueAsString(user);
        System.out.println(json);

        // Convert Json string to Object
        User user2=mapper.readValue(json, User.class);
        System.out.println(user2);

        User user3=new User();
        user3.setAge(33);
        user3.setBirthday(new Date());
        user3.setEmail("123456");
        user3.setmName("jesse3");


        List users = new ArrayList();
        users.add(user);
        users.add(user3);

        // Convert List