对象与JSON之间相互转换 jackson-databind-2.7.0

jackson-databind-2.7.0
Streaming: jackson-core jar，定义了底层的streaming API和实现了Json特性。
Annotations: jackson-annotations jar，包含了标准的Jackson注解。

Databind: jackson-databind jar，实现了数据绑定和对象序列化，它依赖于streaming和annotations的包。

需要的jar：

Maven 依赖：

  <properties>
    <version>0.0.1-SNAPSHOT</version> 
    <jackson.version>2.7.0</jackson.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    
  </properties>
  <dependencies>
    <dependency>  
	  <groupId>com.fasterxml.jackson.core</groupId>  
	  <artifactId>jackson-core</artifactId>  
	  <version>${jackson.version}</version>  
    </dependency>    
    <dependency>  
	  <groupId>com.fasterxml.jackson.core</groupId>  
	  <artifactId>jackson-annotations</artifactId>  
	  <version>${jackson.version}</version>  
    </dependency>
    <dependency>
	  <groupId>com.fasterxml.jackson.core</groupId>
	  <artifactId>jackson-databind</artifactId>
      <version>${jackson.version}</version>
    </dependency>
  </dependencies>

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

public class DataFormatExample {
	public static void main(String[] args) throws Exception {
		ObjectMapper mapper = new ObjectMapper();
		User user1 = new User("lu",1);
		User user2 = new User("deng",0);
		List<User> userList = new ArrayList<User>();
		userList.add(user1);
		userList.add(user2);
		Map<String,User> userMap = new HashMap<String, User>();
		userMap.put("user1", user1);
		userMap.put("user2", user2);
		
		String userFormatJson1 = mapper.writeValueAsString(user1);//对象转JSON
		String userFormatJson2 = mapper.writeValueAsString(user2);
		String listFormatJson = mapper.writeValueAsString(userList);
		String mapFormatJson = mapper.writeValueAsString(userMap);
		System.out.println(userFormatJson1);
		System.out.println(userFormatJson2);
		System.out.println(listFormatJson);
		System.out.println(mapFormatJson);
		
		user1 = mapper.readValue(userFormatJson1, User.class);//JSON转对象
		user2 = mapper.readValue(userFormatJson2, User.class);
		userList = mapper.readValue(listFormatJson, new TypeReference<List<User>>() {});
		userMap = mapper.readValue(mapFormatJson, new TypeReference<Map<String,User>>() {});
		System.out.println(user1);
		System.out.println(user2);
		System.out.println(userList);
		System.out.println(userMap);
	}
}

class User implements Serializable{
	private static final long serialVersionUID = 2417904826221006267L;
	private String name;
	private int sex;//性别；1-男，0-女
	
	public User() {
	}
	
	public String getName() {
		return name;
	}
	
	public void setName(String name) {
		this.name = name;
	}
	
	public int getSex() {
		return sex;
	}
	
	public void setSex(int sex) {
		this.sex = sex;
	}
	
	public User(String name, int sex) {
		this.name = name;
		this.sex = sex;
	}
	
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		result = prime * result + sex;
		return result;
	}
	
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		User other = (User) obj;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		if (sex != other.sex)
			return false;
		return true;
	}
	
	@Override
	public String toString() {
		return "User [name=" + name + ", sex=" + sex + "]";
	}
}