前后的交互js数字精度丢失解决，金额保留两位小数四舍五入统一解决，自定义Json序列化处理方法，@JsonSerialize使用

Posted 2022-02-06 抓手

引入maven坐标

    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
	<dependency>
	    <groupId>com.fasterxml.jackson.core</groupId>
	    <artifactId>jackson-databind</artifactId>
	    <version>2.12.6</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
	<dependency>
	    <groupId>com.fasterxml.jackson.core</groupId>
	    <artifactId>jackson-core</artifactId>
	    <version>2.12.6</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
	<dependency>
	    <groupId>com.fasterxml.jackson.core</groupId>
	    <artifactId>jackson-annotations</artifactId>
	    <version>2.12.6</version>
	</dependency>

js数字精度丢失解决，只需要在参数上加上@JsonSerialize(using = ToStringSerializer.class)就行了，返回给前端回自动将Long转为字符串。

    @JsonSerialize(using = ToStringSerializer.class)
    private Long customerId;

 ToStringSerializer源码：

 

基于ToStringSerializer的源码，我自己定义了金额保留两位小数四舍五入的处理类，只需要继承StdSerializer.class，重写serialize()：

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;

import java.io.IOException;
import java.math.BigDecimal;

/**
 * 保留两位小数，四舍五入保
 *
 * @author 向振华
 * @date 2022/01/14 11:44
 */
public class RoundHalfUpSerializer extends StdSerializer<BigDecimal> 

    protected RoundHalfUpSerializer() 
        super(BigDecimal.class);
    

    public RoundHalfUpSerializer(Class<?> handledType) 
        super(handledType, false);
    

    @Override
    public void serialize(BigDecimal value, JsonGenerator gen, SerializerProvider provider) throws IOException 
        if (value != null) 
            // 这里将BigDecimal 保留两位小数，四舍五入保
            gen.writeNumber(value.setScale(2, BigDecimal.ROUND_HALF_UP));
        
    

然后在字段上加上@JsonSerialize(using = RoundHalfUpSerializer.class)

@Data
public class OrderPageVO 

    @ApiModelProperty(value = "总应缴金额")
    @JsonSerialize(using = RoundHalfUpSerializer.class)
    private BigDecimal totalPayableAmount;

    @ApiModelProperty(value = "总已缴金额")
    @JsonSerialize(using = RoundHalfUpSerializer.class)
    private BigDecimal totalPaidAmount;

这样在返回给前端的json里面就是处理后的数据。

另外还有将日期格式化的@JsonFormat(pattern = "yyyy-MM-dd", timezone = "GMT+8")

忽略序列化的@JsonIgnore

大量注解详见com.fasterxml.jackson.annotation源码。