这取决于你想如何使用你的String。这可以帮助:

String total =  Integer.toString(123) + Double.toString(456.789);

Mostly ditto on SimonJ. I really dislike the ""+i idiom. If you say String.valueOf(i), Java converts the integer to a string and returns the result. If you say ""+i, Java creates a StringBuilder object, appends an empty string to it, converts the integer to a string, appends this to the StringBuilder, then converts the StringBuilder to a String. That's a lot of extra steps. I suppose if you do it once in a big program, it's no big deal. But if you're doing this all the time, you're making the computer do a bunch of extra work and creating all these extra objects that then have to be cleaned up. I don't want to get fanatic about micro-optimization, but I don't want to be pointlessly wasteful either.

正如已经指出的，Integer.toString()或String.valueOf()是正确的方法。我很好奇，做了一个快速的基准测试:

Integer.toString(i)和String.valueOf(i)在性能上基本相同，Integer.toString(i)稍微快一点。但是i + ""要慢1.7倍。

import java.util.Random;

public class Test {

    public static void main(String[] args) {
        long concat = 0;
        long valueOf = 0;
        long toString = 0;
        
        int iterations = 10000;
        int runs = 1000;
        for(int i = 0; i < runs; i++) {
            concat += concat(iterations);
            valueOf += valueOf(iterations);
            toString += to_String(iterations);
        }
        
        System.out.println("concat: " + concat/runs);
        System.out.println("valueOf: " + valueOf/runs);
        System.out.println("toString: " + toString/runs);
    }
    
    public static long concat(int iterations) {
        Random r = new Random(0);
        long start = System.nanoTime();
        for(int i = 0; i < iterations; i++) {
            String s = r.nextInt() + "";
        }
        return System.nanoTime() - start;
    }
    
    public static long valueOf(int iterations) {
        Random r = new Random(0);
        long start = System.nanoTime();
        for(int i = 0; i < iterations; i++) {
            String s = String.valueOf(r.nextInt());
        }
        return System.nanoTime() - start;
    }
    
    public static long to_String(int iterations) {
        Random r = new Random(0);
        long start = System.nanoTime();
        for(int i = 0; i < iterations; i++) {
            String s = Integer.toString(r.nextInt());
        }
        return System.nanoTime() - start;
    }
}

输出:

concat: 1004109
valueOf: 590978
toString: 587236

这取决于你想如何使用你的String。这可以帮助:

String total =  Integer.toString(123) + Double.toString(456.789);

使用Integer.toString (tmpInt) .trim ();

这是可以接受的，但我从来没有写过这样的东西。我更喜欢这样:

String strI = Integer.toString(i);