day08-自定义转换器&处理JSON&内容协商 - ToB企服应用市场:ToB评测及商务社交产业平台

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>save</title>
</head>
<body>
<form action="/saveMonster" method="post">
编号：<input name="id" value="10001"/><br/>
姓名：<input name="name" value="齐天大圣"/><br/>
年龄：<input name="age" value="888"/><br/>
婚否：<input name="isMarried" value="false"/><br/>
生日：<input name="birth" value="1456/12/12"/><br/>
坐骑：<input name="car" value="避水金晶兽,666.6"/><br/>
<input type="submit" value="保存"/>
</form>
</body>
</html>

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package com.li.config;
import com.li.bean.Car;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.converter.Converter;
import org.springframework.format.FormatterRegistry;
import org.springframework.util.ObjectUtils;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/**
* @author 李
* @version 1.0
* (proxyBeanMethods = false)
* 1.表示启用Lite模式，保证修饰的配置类中，每个@Bean方法被调用多少次返回的组件都是新创建的，
* 是多例对象，是非代理方式。
* 2.proxyBeanMethods 在调用 @Bean 方法时才生效，因此需要先获取BeanConfig 组件，再调用方法
*/
@Configuration(proxyBeanMethods = false)//设置为设置类
public class WebConfig {
//注入bean-WebMvcConfigurer
@Bean
public WebMvcConfigurer webMvcConfigurer() {
return new WebMvcConfigurer() {
@Override
public void addFormatters(FormatterRegistry registry) {
/**
* 1.在 addFormatters()方法中添加一个自定义的转换器
* 2.自定义转换器要完成的功能是 String -> Car
* 3.增加的转换器会注册到 converters 容器中
* 4.converters 底层结构是 ConcurrentHashMap，默认内置了124个转换器
*/
registry.addConverter(new Converter<String, Car>() {
//<sourceType,targetType>
//匿名内部类
@Override
public Car convert(String source) {//source即传入的字符串
//加入转换的业务代码
if (!ObjectUtils.isEmpty(source)) {
Car car = new Car();
String[] strings = source.split(",");
car.setName(strings[0]);
car.setPrice(Double.parseDouble(strings[1]));
return car;
}
return null;
}
});
//还可以增加更多的转换器
}
};
}
}

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//处理添加Monster的方法
@PostMapping("/saveMonster")
@ResponseBody
public String saveMonster(Monster monster) {
System.out.println("monster=" + monster);
return "success";
}

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monster=Monster(id=10001, name=齐天大圣, age=888, isMarried=false, birth=Sun Dec 12 00:00:00 CST 1456, car=Car(name=避水金晶兽, price=666.6))

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package com.li.controller;
import com.li.bean.Car;
import com.li.bean.Monster;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.Date;
/**
* @author 李
* @version 1.0
*/
@Controller
public class ResponseController {
//编写方法，以json格式返回数据
@GetMapping("/get/monster")
@ResponseBody
public Monster getMonster() {
Monster monster = new Monster();
monster.setId(199);
monster.setName("孙悟空");
monster.setAge(23);
monster.setIsMarried(false);
monster.setBirth(new Date());
Car car = new Car();
car.setName("奔驰");
car.setPrice(20000.0);
monster.setCar(car);
return monster;
}
}

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//参数Object object就是控制器方法返回的对象类型，如Monster
protected void writeInternal(Object object, @Nullable Type type, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
//当控制器方法返回的时候，获取返回对象的contentType，一般为application/json
MediaType contentType = outputMessage.getHeaders().getContentType();
//获取编码，一般为utf-8
JsonEncoding encoding = this.getJsonEncoding(contentType);
Class<?> clazz = object instanceof MappingJacksonValue ? ((MappingJacksonValue)object).getValue().getClass() : object.getClass();
ObjectMapper objectMapper = this.selectObjectMapper(clazz, contentType);
Assert.state(objectMapper != null, "No ObjectMapper for " + clazz.getName());
OutputStream outputStream = StreamUtils.nonClosing(outputMessage.getBody());
try {//生成一个UTF8JsonGenerator对象
JsonGenerator generator = objectMapper.getFactory().createGenerator(outputStream, encoding);
Throwable var10 = null;
try {//对返回的数据类型进行一系列处理
this.writePrefix(generator, object);
Object value = object;
Class<?> serializationView = null;
FilterProvider filters = null;
JavaType javaType = null;
if (object instanceof MappingJacksonValue) {
MappingJacksonValue container = (MappingJacksonValue)object;
value = container.getValue();
serializationView = container.getSerializationView();
filters = container.getFilters();
}
if (type != null && TypeUtils.isAssignable(type, value.getClass())) {
javaType = this.getJavaType(type, (Class)null);
}
ObjectWriter objectWriter = serializationView != null ? objectMapper.writerWithView(serializationView) : objectMapper.writer();
if (filters != null) {
objectWriter = objectWriter.with(filters);
}
if (javaType != null && javaType.isContainerType()) {
objectWriter = objectWriter.forType(javaType);
}
SerializationConfig config = objectWriter.getConfig();
if (contentType != null && contentType.isCompatibleWith(MediaType.TEXT_EVENT_STREAM) && config.isEnabled(SerializationFeature.INDENT_OUTPUT)) {
objectWriter = objectWriter.with(this.ssePrettyPrinter);
}
//UTF8JsonGenerator对象处理返回的数据
objectWriter.writeValue(generator, value);
this.writeSuffix(generator, object);
generator.flush();
} catch (Throwable var26) {
var10 = var26;
throw var26;
} finally {
if (generator != null) {
if (var10 != null) {
try {
generator.close();
} catch (Throwable var25) {
var10.addSuppressed(var25);
}
} else {
generator.close();
}
}
}
} catch (InvalidDefinitionException var28) {
throw new HttpMessageConversionException("Type definition error: " + var28.getType(), var28);
} catch (JsonProcessingException var29) {
throw new HttpMessageNotWritableException("Could not write JSON: " + var29.getOriginalMessage(), var29);
}
}

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<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
</dependency>

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spring:
mvc:
contentnegotiation:
favor-parameter: true #开启基于请求参数的内容协商，默认不开启

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