SpringMVC 自定义序列化规则

你的名字 2022-04-16 00:44 915阅读 0赞

### 文章目录 ###

本文讲解如何如何自定义SpringMVC的序列化规则

使用SpringBoot为例，SpringBoot默认使用Jackson作为序列化工具。通过修改Jackson配置即可自定义序列化规则。

**方法1**

一般需要为第三方java类实现序列化规则使用，这里以boolean转int为例(true/false->1/0)，代码如下

// 1 编写自定义序列化类，实现JsonSerializer接口
    public class BooleanSerializer extends JsonSerializer<Boolean> { 
        @Override
        public void serialize(Boolean value, JsonGenerator gen, SerializerProvider serializers) throws IOException { 
            if (value != null && value) { 
                gen.writeNumber(1);
            } else { 
                gen.writeNumber(0);
            }
        }
    }
    // 2 测试
    public class Test { 
        @Test
        public void globalSerialize() throws JsonProcessingException { 
            ObjectMapper objectMapper = new ObjectMapper();
            SimpleModule simpleModule = new SimpleModule();
            BooleanSerializer serializer = new BooleanSerializer();
            simpleModule.addSerializer(Boolean.class,serializer);
            simpleModule.addSerializer(boolean.class,serializer);
            objectMapper.registerModule(simpleModule);
            // 输出 1
            System.out.println(objectMapper.writeValueAsString(true));
        }
    }

在SpringBoot中只要将SimpleModule注册到容器中，容器会自动配置到Jackson上。全部配置代码如下，测试略

@Configuration
    public class JacksonConfig { 
        /** * 自定义boolean类型序列化规则 */
        static class BooleanSerializer extends JsonSerializer<Boolean> { 
            @Override
            public void serialize(Boolean value, JsonGenerator gen, SerializerProvider serializers) throws IOException { 
                if (value != null && value) { 
                    gen.writeNumber(1);
                } else { 
                    gen.writeNumber(0);
                }
            }
        }
        @Bean
        public SimpleModule simpleModule() { 
            SimpleModule module = new SimpleModule();
            BooleanSerializer serializer = new BooleanSerializer();
            module.addSerializer(Boolean.class, serializer);
            module.addSerializer(boolean.class, serializer);
            return module;
        }
    
    }

**方法2**

自定义java类使用，以User类为例

@Data
    public class User { 
    	private Integer id;
    	private String name;
    }
    // 1 自定义序列化类实现JsonSerializer接口
    public static class UserSerializer extends JsonSerializer<User> { 
    	// 假设序列化时，为每个字段增加u前缀
    	@Override
    	public void serialize(User value, JsonGenerator gen, SerializerProvider serializers) throws IOException { 
    		gen.writeStartObject();
    		gen.writeNumberField("uid", value.getId());
    		gen.writeStringField("uname", value.getName());
    		gen.writeEndObject();
    	}
    }
    // 2 通过@JsonSerialize注解指定序列化类
    @JsonSerialize(using = UserSerializer.class)
    public static class User { 略}
    // 3 测试
    public class Test { 
    	@Test
    	public void serializer() throws IOException { 
    		ObjectMapper objectMapper = new ObjectMapper();
    		User user = new User();
    		user.setId(1);
    		user.setName("ly");
    		String json = objectMapper.writeValueAsString(user);
    		// 输出 {"uid":1,"uname":"ly"}
    		System.out.println(json);
    	}
    }