Log4j不仅能通过XML配置，也能通过JSON配置。如你所知，JSON的格式非常类似于紧凑版XML。每个键代表了插件名称，对应的值是属性。键中可以有子级插件。如下，“ThresholdFilter, Console, PatternLayout”都是插件。Console的值是“STDOUT”，意为日志控制台输出；“ThresholdFilter”的值是被设为调试级。
{ "configuration": { "status": "error", "name": "RoutingTest", "packages": "org.apache.logging.log4j.test", "properties": { "property": { "name": "filename", "value" : "target/rolling1/rollingtest-$${sd:type}.log" } }, "ThresholdFilter": { "level": "debug" }, "appenders": { "Console": { "name": "STDOUT", "PatternLayout": { "pattern": "%m%n" } }, "List": { "name": "List", "ThresholdFilter": { "level": "debug" } }, "Routing": { "name": "Routing", "Routes": { "pattern": "$${sd:type}", "Route": [ { "RollingFile": { "name": "Rolling-${sd:type}", "fileName": "${filename}", "filePattern": "target/rolling1/test1-${sd:type}.%i.log.gz", "PatternLayout": {"pattern": "%d %p %c{1.} [%t] %m%n"}, "SizeBasedTriggeringPolicy": { "size": "500" } } }, { "AppenderRef": "STDOUT", "key": "Audit"}, { "AppenderRef": "List", "key": "Service"} ] } } }, "loggers": { "logger": { "name": "EventLogger", "level": "info", "additivity": "false", "AppenderRef": { "ref": "Routing" }}, "root": { "level": "error", "AppenderRef": { "ref": "STDOUT" }} } } } 注意，在路径追加器中，“Route”元素被声明为数组，这是可行的，因为每个数组元素都是“Route”。然而，在单纯的追加器和过滤器中就不行了，因为在JSON格式里，每个元素都有不同的名称。只有当追加器和过滤器声明是类型的时候，它们才可以由数组定义。如下展现了通过数组定义了多路logger。{ “configuration”: { “status”: “debug”, “name”: “RoutingTest”, “packages”: “org.apache.logging.log4j.test”, “properties”: { “property”: { “name”: “filename”, “value” : “target/rolling1/rollingtest-$${sd:type}.log” } }, “ThresholdFilter”: { “level”: “debug” }, “appenders”: { “appender”: [ { “type”: “Console”, “name”: “STDOUT”, “PatternLayout”: { “pattern”: “%m%n” }}, { “type”: “List”, “name”: “List”, “ThresholdFilter”: { “level”: “debug” }}, { “type”: “Routing”, “name”: “Routing”, “Routes”: { “pattern”: “$${sd:type}”, “Route”: [ { “RollingFile”: { “name”: “Rolling-${sd:type}”, “fileName”: “${filename}”, “filePattern”: “target/rolling1/test1-${sd:type}.%i.log.gz”, “PatternLayout”: {“pattern”: “%d %p %c{1.} [%t] %m%n”}, “SizeBasedTriggeringPolicy”: { “size”: “500” } } }, { “AppenderRef”: “STDOUT”, “key”: “Audit”}, { “AppenderRef”: “List”, “key”: “Service”} ] } } ] }, “loggers”: { “logger”: [ { “name”: “EventLogger”, “level”: “info”, “additivity”: “false”, “AppenderRef”: { “ref”: “Routing” }}, { “name”: “com.foo.bar”, “level”: “error”, “additivity”: “false”, “AppenderRef”: { “ref”: “Console” }} ], “root”: { “level”: “error”, “AppenderRef”: { “ref”: “STDOUT” }} } } }
通过Jackson数据处理器来提供JSON文件的解析支持。你需要给项目添加如下依赖：
com.fasterxml.jackson.core jackson-core 2.8.3
com.fasterxml.jackson.core jackson-databind 2.8.3
com.fasterxml.jackson.core jackson-annotations 2.8.3
转载自 并发编程网 - ifeve.com
