我們都知道spring boot或者springmvc可以藉助自帶的jackson直接把實體物件裝成json，這次不是分享關於框架如何返回json,而是要給大家分享實體類裡的date型別的欄位在返回時怎麼統一處理成統一返回成string型別

1 使用註解類讓其繼承JsonSerializer，如下所示

package com.debug;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

public class CustomDateSerializer extends JsonSerializer<Date>{

	@Override
	public void serialize(Date value, JsonGenerator jgen, SerializerProvider arg2)
			throws IOException, JsonProcessingException {
		// TODO Auto-generated method stub
		SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        String formattedDate = formatter.format(value);
        jgen.writeString(formattedDate);
		
	}

}
 

public class UserInfo {
	private String name;
	private int id;
	private Date birthday;
	
	@JsonSerialize(using = CustomDateSerializer.class)
	public Date getBirthday() {
		return birthday;
	}

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

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	
}
 

3  controller的測試程式碼

package com.debug;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HiController {
  
   @RequestMapping("/getUserInfo.do")
   public List<UserInfo> getUserInfo() {
	   
	   UserInfo u1=new UserInfo();
	   u1.setId(1);
	   u1.setName("justin timberlake");
	   u1.setBirthday(new Date());
	   
	   UserInfo u2=new UserInfo();
	   u2.setId(2);
	   u2.setName("林志穎");
	   u2.setBirthday(new Date());
	   
	   List<UserInfo> userList=new ArrayList<UserInfo>();
	   userList.add(u1);
	   userList.add(u2);
	
	   return userList;
   }
   
  
}