Java中构建长字符串的四种模式

回字有四种写法，构建字符串也有四种方式。

用+号最快，第二第三种可读性好，第四种是log4j自有的。下面请见代码：

package logbackCfg;

import java.text.MessageFormat;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

public class StringContructor {

    private final static Logger logger = LoggerFactory.getLogger(StringContructor.class);

    public static void main(String[] arges) {

        int count=5;

        String city="Dalian";

        // 1.Traditional and fastest String construction pattern

        System.out.println("There are "+count+" million people live in "+city+".");

        // 2.String.format pattern

        System.out.println(String.format("There are %d million people live in %s.", count,city));

        // 3.MessageFormat pattern

        String raw="There are {0} million people live in {1}.";

        Object[] arr={String.valueOf(count),city};

        String result=MessageFormat.format(raw, arr);

        System.out.println(result);

        // 4.log4j/logback built-in pattern

        logger.info("There are {} million people live in {}.",count,city);

    }

}

输出：

There are 5 million people live in Dalian.

There are 5 million people live in Dalian.

There are 5 million people live in Dalian.

2020-03-06 16:51:25.394 [main] INFO  logbackCfg.StringContructor -There are 5 million people live in Dalian.

--2020-03-06--