SpringMVC---Json的使用

1.所需文件

2.pom中加入json

    
    
        springmvc
        org.springframework.web.servlet.DispatcherServlet
        
        
            contextConfigLocation
            classpath:springmvc-servlet.xml
        
        
        1
    
    
    
    
        springmvc
        /
    
    
    
        encoding
        org.springframework.web.filter.CharacterEncodingFilter
        
            encoding
            utf-8
        
    
    
        encoding
        /
    

3.springmvc-servlet.xml

4.web.xml

    
    
        springmvc
        org.springframework.web.servlet.DispatcherServlet
        
        
            contextConfigLocation
            classpath:springmvc-servlet.xml
        
        
        1
    
    
    
    
        springmvc
        /
    
    
    
        encoding
        org.springframework.web.filter.CharacterEncodingFilter
        
            encoding
            utf-8
        
    
    
        encoding
        /
    

5.实体类

package com.shao.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private String name;
    private int age;
    private String sex;
}

5.UserController

package com.shao.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.shao.pojo.User;
import com.shao.utils.JsonUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;

//@Controller 视图
@RestController //会直接返回一个字符串，是对整个类做注解的
public class UserController {

    @RequestMapping("/json1")
    //@ResponseBody //不会走视图解析器，会直接返回一个字符串
    public String json1() throws JsonProcessingException {
        //创建一个jackson的对象映射器，用来解析数据
        ObjectMapper mapper = new ObjectMapper();
        //创建一个对象
        User user = new User("shao", 3, "男");
        //将我们的对象解析成为json格式
        String str = mapper.writeValueAsString(user);
        //由于@ResponseBody注解，这里会将str转成json格式返回；十分方便
        return str;
    }

    @RequestMapping("/json2")
    public String json2() throws JsonProcessingException {
        //创建一个jackson的对象映射器，用来解析数据
        ObjectMapper mapper = new ObjectMapper();
        //创建对象
        ArrayList users = new ArrayList();
        users.add(new User("邵哲明", 3, "男"));
        users.add(new User("嬲", 3, "男"));
        users.add(new User("嬲到了", 3, "男"));
        users.add(new User("去你码的", 3, "男"));
        //将我们的对象解析成为json格式
        String str = mapper.writeValueAsString(users);
        return str;
    }

    @RequestMapping("/json3")
    public String json3() throws JsonProcessingException {

        ObjectMapper mapper = new ObjectMapper();

        //创建时间一个对象，java.util.Date
        Date date = new Date();
        //将我们的对象解析成为json格式
        String str = mapper.writeValueAsString(date);
        return str;
    }
    @RequestMapping("/json4")
    public String json4() throws JsonProcessingException {

        ObjectMapper mapper = new ObjectMapper();

        //不使用时间戳的方式
        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        //自定义日期格式对象
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        //指定日期格式
        mapper.setDateFormat(sdf);

        Date date = new Date();
        String str = mapper.writeValueAsString(date);

        return str;
    }
    @RequestMapping("/json5")
    public String json5() throws JsonProcessingException {
        Date date = new Date();
        String json = JsonUtils.getJson(date);
        return json;
    }
}

6.封装成工具类Utils

package com.shao.utils;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

import java.text.SimpleDateFormat;

public class JsonUtils {

    public static String getJson(Object object) {
        return getJson(object,"yyyy-MM-dd HH:mm:ss");
    }

    public static String getJson(Object object,String dateFormat) {
        ObjectMapper mapper = new ObjectMapper();
        //不使用时间差的方式
        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        //自定义日期格式对象
        SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);
        //指定日期格式
        mapper.setDateFormat(sdf);
        try {
            return mapper.writeValueAsString(object);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }
}