编辑页面数据初始化时,一条数据中的某个字段,java后台怎么返回给前端数组

spring方式

package com.learn;

import lombok.extern.log4j.Log4j2;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.Mapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.*;

@SpringBootApplication
@Log4j2
@RestController
public class LearnConcurrencyApplication {

   public static void main(String[] args) {
      SpringApplication.run(LearnConcurrencyApplication.class, args);
   }

   @GetMapping("/")
   public String test() {
      log.warn("Receive request.");
      return "test";
   }

   @GetMapping("/a")
   public Map<String,Object> getA() {
      StudentInfo info = new StudentInfo();

      //方式1，假设字段a是字符串
//    info.setA("1,2,3,4,5,6");
//    Map<String,Object> result = new HashMap<>();
//    result.put("A",Arrays.asList(info.getA().split(",")));
//    return result;

      //假设A是list
      List<String> list = Arrays.asList("1,2,3,4,5,6".split(","));
      info.setA1(list);
      Map<String,Object> result = new HashMap<>();
      result.put("A",info.getA1());
      return result;
   }

   @Bean
   public ServletRegistrationBean servletRegistration() {
      ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
      servletRegistrationBean.addUrlMappings("/sa");
      servletRegistrationBean.setServlet(new MyServlet());
      return servletRegistrationBean;
   }
}

servlet方式，注意依赖jackson，jar包

package com.learn;

import com.fasterxml.jackson.databind.ObjectMapper;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author lixiaosuo
 * @since 2019-04-12 10:05
 */
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        StudentInfo info = new StudentInfo();
        List<String> list = Arrays.asList("1,2,3,4,5,6".split(","));
        info.setA1(list);
        Map<String,Object> result = new HashMap<>();
        result.put("A",info.getA1());

        //依赖jackson
        ObjectMapper mapper = new ObjectMapper();
        String json =mapper.writeValueAsString(result);

        resp.setContentType("application/json;charset=utf-8");
        resp.setCharacterEncoding("utf-8");
        resp.getWriter().write(json);
        resp.getWriter().flush();
        resp.getWriter().close();
    }
}

辅助类

package com.learn;

import java.util.List;

/**
 * @author lixiaosuo
 * @since 2019-04-12 09:46
 */
public class StudentInfo {

    public String a;
    public List<String> a1;

    public String getA() {
        return a;
    }

    public void setA(String a) {
        this.a = a;
    }

    public List<String> getA1() {
        return a1;
    }

    public void setA1(List<String> a1) {
        this.a1 = a1;
    }
}

spring实现，输出结果：

servlet，实现输出结果