文章目录

1、什么是fastjson2、pom.xml 配置3、全局WebMvcConfig配置5、闭坑指南

1、什么是fastjson

<code>fastjson是阿里巴巴开发的一个高性能的Java JSON处理库，它支持将Java对象转换成JSON格式，同时也支持将JSON字符串解析成Java对象。

2、pom.xml 配置

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

<exclusions>

<exclusion>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-json</artifactId>

</exclusion>

</exclusions>

</dependency>

<dependency>

<groupId>com.alibaba</groupId>

<artifactId>fastjson</artifactId>

<version>1.2.79</version>

</dependency>

3、全局WebMvcConfig配置

package com.gis.fastjson.config;

import com.alibaba.fastjson2.JSONReader;

import com.alibaba.fastjson2.JSONWriter;

import com.alibaba.fastjson2.support.config.FastJsonConfig;

import com.alibaba.fastjson2.support.spring.http.converter.FastJsonHttpMessageConverter;

import org.springframework.context.annotation.Configuration;

import org.springframework.http.MediaType;

import org.springframework.http.converter.HttpMessageConverter;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.nio.charset.StandardCharsets;

import java.util.Collections;

import java.util.List;

@Configuration

public class WebMvcConfig implements WebMvcConfigurer {

@Override

public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {

FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();

//custom configuration

FastJsonConfig config = new FastJsonConfig();

config.setDateFormat("yyyy-MM-dd HH:mm:ss");

config.setReaderFeatures(JSONReader.Feature.FieldBased, JSONReader.Feature.SupportArrayToBean);

config.setWriterFeatures(JSONWriter.Feature.WriteMapNullValue, JSONWriter.Feature.PrettyFormat);

converter.setFastJsonConfig(config);

converter.setDefaultCharset(StandardCharsets.UTF_8);

converter.setSupportedMediaTypes(Collections.singletonList(MediaType.APPLICATION_JSON));

converters.add(0, converter);

}

}

4、controller测试

package com.gis.fastjson.controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;

import java.util.Map;

@RestController

public class HelloWorldController {

@RequestMapping("/test")

public Map<String, Object> showHelloWorld(){

Map<String, Object> map = new HashMap<>();

map.put("msg", "Hello World!");

return map;

}

}

5、闭坑指南

BigDecimal精度丢失

@Test

public void toJSONString() throws ParseException {

BookDTO book = new BookDTO();

BigDecimal money = new BigDecimal(-40090.07d);

money = book.setScale(4, RoundingMode.HALF_UP);

book.setMoney(money);

String createtime ="2024-07-22 09:03:26.968";

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");

Date date = format.parse(createtime);

book.setCreateTime(date);

List<BookDTO> list = new ArrayList<>();

list.add(book);

String json =J SON.toJSONString(list);

System.out.println(json);

// 解决方法

// String json = JSON.toJSONString(list, JSONWriter.Feature.WriteBigDecimalAsPlain);

}

}

日期解析问题

@Test

public void parseArray() {

String json="[{\"create_time\":\"2024-07-22 10:03:26.968\",\"money\":-40090.0700}]";code>

System.out.println(json);

List<BookDTO> list1 = JSON.parseArray(json, BookDTO.class,JSONReader.Feature.SupportSmartMatch);

System.out.println();

}

运行结果

java.time.format.DateTimeParseException: Text ‘2024-07-22 10:03:26.968’ could not be parsed, unparsed text found at index 10

解决方法

BookDTO上加上@JSONField(format= “yyyy-MM-dd HH:mm:ss”)