Spring 架构中,可以使用@Value
注解从配置文件或命令行参数中获取集合数据。
各种示例
- 获取基础类型
当没有配置时,可以设置默认值。无默认值时会抛出空值异常。
@Value("${lizz.timeout:3000}")
private int timeout;
@Value("${lizz.key:lizzkey}")
private String key;
- 获取列表数据
lizz.list=a,b,c
@Value("${lizz.list}")
private List<String> list;
@Value("${lizz.list}")
private String[] arrStr;
- 获取Map数据
lizz.map={"key1":"value1","key2":"value2"}
@Value("#{${lizz.map}}")
private Map<String, String> map;
- 使用SpEL表达式
lizz.list2 = 1;2;3
@Value("#{'${lizz.list2}'.split(';')}")
private List<Integer> integerList;
验证
lizz.list1 = a,b,c
lizz.list2 = 1;2;3
lizz.map = {"key1":"value1","key2":"value2"}
@Component
public class MyApplication {
@Value("${lizz.list1}")
private String str;
@Value("${lizz.list1}")
private List<String> list1;
@Value("${lizz.list1}")
private String[] arrStr;
@Value("#{${lizz.map}}")
private Map<String, String> map1;
/*
获取lizz.list2,并对;号进行分隔生成list
*/
@Value("#{'${lizz.list2}'.split(';')}")
private List<Integer> integerList;
public static void main(String[] args) {
SpringApplication.run(MyApplication.class, args);
System.out.println("str=" + str);
System.out.println("list1=" + list1);
System.out.println("arrStr=" + arrStr);
System.out.println("map1=" + map1);
System.out.println("integerList=" + integerList);
}
}
str=a,b,c
list1=[a, b, c]
arrStr=[Ljava.lang.String;@79d3c655
map1={key1=value1, key2=value2}
integerList=[1, 2, 3]