SpringBootWeb应用程序中的响应如何转换为JSON?
我的 pom 中没有包含 jackson-databind。但是,当我调用一个返回一个对象的端点时,它被转换为 JSON。如果我的 pom 不包含 jackson-databind 响应如何转换为 JSON。
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.0</version>
<relativePath />
</parent>
<dependencies>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
@RestController 公共类 TradeController {
@RequestMapping("/trade")
public Trade hello() {
String helloWorldMessage = "Hello world from java2blog!";
Trade t = new Trade();
t.setId(1);
return t;
}
}
调用 http://localhost:8080/trade 返回 {"id":1}
回答
如果运行mvn dependency:tree,您将看到默认情况下随spring-boot-starter-web依赖项一起包含的所有依赖项。请注意,包含 jackson-databind。
前任:
[INFO] +- org.springframework.boot:spring-boot-starter-web:jar:2.4.3:compile
[INFO] | +- org.springframework.boot:spring-boot-starter-json:jar:2.4.3:compile
[INFO] | | +- com.fasterxml.jackson.core:jackson-databind:jar:2.11.4:compile
[INFO] | | | +- com.fasterxml.jackson.core:jackson-annotations:jar:2.11.4:compile
[INFO] | | | - com.fasterxml.jackson.core:jackson-core:jar:2.11.4:compile
[INFO] | | +- com.fasterxml.jackson.datatype:jackson-datatype-jdk8:jar:2.11.4:compile
[INFO] | | +- com.fasterxml.jackson.datatype:jackson-datatype-jsr310:jar:2.11.4:compile
[INFO] | | - com.fasterxml.jackson.module:jackson-module-parameter-names:jar:2.11.4:compile
[INFO] | +- org.springframework.boot:spring-boot-starter-tomcat:jar:2.4.3:compile
[INFO] | | +- org.apache.tomcat.embed:tomcat-embed-core:jar:9.0.43:compile
[INFO] | | +- org.glassfish:jakarta.el:jar:3.0.3:compile
[INFO] | | - org.apache.tomcat.embed:tomcat-embed-websocket:jar:9.0.43:compile
[INFO] | +- org.springframework:spring-web:jar:5.3.4:compile
[INFO] | | - org.springframework:spring-beans:jar:5.3.4:compile
[INFO] | - org.springframework:spring-webmvc:jar:5.3.4:compile
[INFO] | +- org.springframework:spring-aop:jar:5.3.4:compile
[INFO] | - org.springframework:spring-expression:jar:5.3.4:compile
在幕后,spring 正在利用 jackson 模块将您的响应转换为 JSON。