What are the differences between @autowired and @resource?

Difference: 1. @Autowired is provided by Spring, @Resource is provided by J2EE, and requires JDK1.6 and above; 2. @Autowired is only injected according to byType, @Resource is automatically injected by byName by default, and is also provided Inject according to byType.

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is often used in Spring 3.X @Autowired and @Resource for assembly.

I can’t help but wonder what is the difference between these two annotations? ? ?

Similar points:

@Resource is equivalent to @Autowired, and can be marked on the setter method of a field or attribute.

Differences:

(1) Provider: @Autowired is provided by org.springframework.beans.factory.annotation.Autowired, in other words it is provided by Spring Provided; @Resource is provided by javax.annotation.Resource, which is provided by J2EE and requires JDK1.6 and above.

(2) Injection method: @Autowired only injects according to byType; @Resource automatically injects by byName by default, and also provides injection according to byType;

(3) Attributes: @Autowired assembles dependencies by type Object, by default it requires that the dependent object must exist. If null values ​​are allowed, you can set its required attribute to false. If we want to use assembly by name, we can use it in conjunction with the @Qualifier annotation. @Resource has two important attributes: name and type. The name attribute specifies byName. If the name attribute is not specified, when the annotation is annotated on the field, the name of the field is used as the bean name by default to find the dependent object. When the annotation is annotated on the setter method of the attribute, the attribute name is used as the bean name by default. Dependent objects. It should be noted that if @Resource does not specify a name attribute and the dependent object cannot be found according to the default name, the @Resource annotation will fall back to assembly by type. But once the name attribute is specified, it can only be assembled by name.

@Resource Assembly Sequence

1. If name and type are specified at the same time, the only matching bean will be found from the Spring context for assembly. If it is not found, it will be thrown. Exception

　2. If name is specified, the bean matching the name (id) will be searched from the context for assembly. If no bean is found, an exception will be thrown

　3. If type is specified, Then find the only bean with matching type from the context for assembly. If no bean is found or multiple are found, an exception will be thrown

　4. If neither name nor type is specified, the byName method will be automatically used. Assembly; if there is no match, it will fall back to a primitive type for matching, and if it matches, it will be automatically assembled;

It is recommended to use @Resource annotation on the field, so that there is no need to write a setter method. And this annotation belongs to J2EE reduces the coupling with Spring, so the code looks more elegant.

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