springboot配置Gson

1.引入依赖

<dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <exclusions>
          <exclusion>
              <groupId>com.fasterxml.jackson.core</groupId>
              <artifactId>jackson-databind</artifactId>
          </exclusion>
      </exclusions>
</dependency>
<dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
</dependency>

解释：springboot默认使用Jackson-databind作为JSON处理器，使用Gson就需要先剔除jackson-databind

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2.源码分析

···
···
@Bean
@ConditionalOnMissingBean
public GsonHttpMessageConverter gsonHttpMessageConverter(Gson gson) {
    GsonHttpMessageConverter converter = new GsonHttpMessageConverter();
    converter.setGson(gson);
     return converter;
}

解释： 以上是GsonHttpMessageConverterConfiguration中的一段源码，由@ConditionalOnMissingBean可知，我们可以自己配置GsonHttpMessageConverter来替换默认的配置

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3.Gson自定义配置

@Configuration
public class GsonConfig {

    @Bean
    GsonHttpMessageConverter gsonHttpMessageConverter(){
        GsonHttpMessageConverter converter =  new GsonHttpMessageConverter();
        GsonBuilder builder = new GsonBuilder();
        //设置日期格式
        builder.setDateFormat("yyyy-MM-dd");
        //设置过滤修饰符为protected的字段
        builder.excludeFieldsWithModifiers(Modifier.PROTECTED);
        Gson gson = builder.create();
        converter.setGson(gson);
        return converter;
    }
}

4.测试

• 先定义一个model

@Getter
@Setter
@AllArgsConstructor
public class Book {
    private String name;
    private String author;
    //此字段在输出时将会被忽略
    protected float price;
    private Date date;
}

• 定义路由

@RestController
public class BookController {

    @GetMapping("/book")
    public Book book(){
        return new Book("小罗","小三",30f,new Date());
    }
}

• 接口调用
  使用浏览器访问http://localhost:8080/book,页面展示如下：

{"name":"小罗","author":"小三","date":"2020-11-07"}

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5.fastjson配置
fastjson配置请看文章：springboot配置fastjson