Java中構建長字符串的四種模式

回字有四種寫法，構建字符串也有四種方式。

用+號最快，第二第三種可讀性好，第四種是log4j自有的。下面請見代碼：

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);
    }
}

輸出：

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--