Spring MVC自定义消息转换器(可解决Long类型数据传入前端精度丢失的问题)

方法一 jackson注解

<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.8.6</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.8.6</version>
</dependency>

package com.paascloud.helper;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

import java.io.IOException;

/**
* Long 类型字段序列化时转为字符串，避免js丢失精度
*/
public class LongJsonSerializer extends JsonSerializer<Long> {
/**
* Serialize.
*
* @param value              the value
* @param jsonGenerator      the json generator
* @param serializerProvider the serializer provider
*
* @throws IOException the io exception
*/
@Override
public void serialize(Long value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
String text = (value == null ? null : String.valueOf(value));
if (text != null) {
jsonGenerator.writeString(text);
}
}
}

package com.paascloud.helper;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

/**
* 将字符串转为Long
*/
public class LongJsonDeserializer extends JsonDeserializer<Long> {
private static final Logger logger = LoggerFactory.getLogger(LongJsonDeserializer.class);

/**
* Deserialize long.
*
* @param jsonParser             the json parser
* @param deserializationContext the deserialization context
*
* @return the long
*
*/
@Override
public Long deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) {
String value = null;
try {
value = jsonParser.getText();
} catch (IOException e) {
e.printStackTrace();
}
try {
return value == null ? null : Long.parseLong(value);
} catch (NumberFormatException e) {
logger.error("解析长整形错误", e);
return null;
}
}
}

@Data
public class BaseEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@JsonSerialize(using = LongJsonSerializer.class)
@JsonDeserialize(using = LongJsonDeserializer.class)
private Long id;
}

方法二

<!-- https://mvnrepository.com/artifact/org.apache.rocketmq/rocketmq-client -->
<dependency>
<groupId>org.apache.rocketmq</groupId>
<artifactId>rocketmq-client</artifactId>
<version>4.1.0-incubating</version>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>

@Bean
public ObjectMapper ObjectMapper(){
SimpleModule simpleModule = new SimpleModule();
simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
ObjectMapper objectMapper = new ObjectMapper()
.registerModule(new ParameterNamesModule())
.registerModule(new Jdk8Module())
.registerModule(new JavaTimeModule())
.registerModule(simpleModule);
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
//      Seriali
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zerProvider serializerProvider = objectMapper.getSerializerProvider();
//      serializerProvider.setNullValueSerializer(new JsonSerializer<Object>() {
//          @Override
//          public void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
//              jsonGenerator.writeString("");
//          }
//
//      });
return objectMapper;
}