Java中用for输出1+2+3+....n＜=1000

可以使用for循环来实现，代码如下：

int sum = 0;
for (int i = 1; i <= n; i++) {
    sum += i;
    if (sum > 1000) {
        break;
    }
    System.out.print(i + "+");
}
System.out.println("\b=" + sum);

这里使用了一个变量sum来记录累加的结果，当sum大于1000时，退出循环。同时，在输出过程中，使用了\b来删除最后一个"+"号。

相关问题

java中用一维数组输入一个n个学生的成绩,并从高到低顺序输出

可以使用Java中的Arrays类提供的sort方法进行排序，然后再倒序输出数组即可。具体代码如下：

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        int[] scores = {90, 80, 95, 85, 88}; // 假设有5个学生的成绩
        Arrays.sort(scores); // 数组排序，默认升序
        for (int i = scores.length - 1; i >= 0; i--) { // 倒序输出数组
            System.out.print(scores[i] + " ");
        }
    }
}

输出结果为：

95 90 88 85 80 

在Java中用Dom4j把这一段xml内容转成Map对象：<?xml version="1.0" encoding="UTF-8"?> <java version="1.6.0_26" class="java.beans.XMLDecoder"> <object class="java.util.HashMap"> <void method="put"> <string>att_20160719180419281NEk9</string> <string>cx</string> </void> <void method="put"> <string>att_20160511094248589ZKYq</string> <string>cnmm</string> </void> <void method="put"> <string>att_20161018153614188aTus</string> <string>zsx;fj</string> </void> <void method="put"> <string>att_20160422110906494XuEf</string> <null/> </void> <void method="put"> <string>att_20160511130210612UULE</string> <string>fjyxapp;jjgjapp;wx;jd;dxjg;tb;wsjy</string> </void> <void method="put"> <string>att_20160719180542840LnFm</string> <string></string> </void> <void method="put"> <string>att_20160511130025203ssle</string> <string>zdgsszta</string> </void> <void method="put"> <string>att_20160810131359346N0ra</string> <string>szjys</string> </void> <void method="put"> <string>att_20160511130031927equg</string> <string></string> </void> <void method="put"> <string>att_20160422110456036qp7Y</string> <null/> </void> <void method="put"> <string>att_20160422110543585f7iI</string> <string>cpjbxx</string> </void> </object> </java>

您可以使用以下代码将该XML转换为Map对象：

import java.io.StringReader;
import java.util.HashMap;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class XmlToMap {
    public static void main(String[] args) throws Exception {
        String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>  <java version=\"1.6.0_26\" class=\"java.beans.XMLDecoder\">   <object class=\"java.util.HashMap\">    <void method=\"put\">     <string>att_20160719180419281NEk9</string>     <string>cx</string>    </void>    <void method=\"put\">     <string>att_20160511094248589ZKYq</string>     <string>cnmm</string>    </void>    <void method=\"put\">     <string>att_20161018153614188aTus</string>     <string>zsx;fj</string>    </void>    <void method=\"put\">     <string>att_20160422110906494XuEf</string>     <null/>    </void>    <void method=\"put\">     <string>att_20160511130210612UULE</string>     <string>fjyxapp;jjgjapp;wx;jd;dxjg;tb;wsjy</string>    </void>    <void method=\"put\">     <string>att_20160719180542840LnFm</string>     <string></string>    </void>    <void method=\"put\">     <string>att_20160511130025203ssle</string>     <string>zdgsszta</string>    </void>    <void method=\"put\">     <string>att_20160810131359346N0ra</string>     <string>szjys</string>    </void>    <void method=\"put\">     <string>att_20160511130031927equg</string>     <string></string>    </void>    <void method=\"put\">     <string>att_20160422110456036qp7Y</string>     <null/>    </void>    <void method=\"put\">     <string>att_20160422110543585f7iI</string>     <string>cpjbxx</string>    </void>   </object>  </java>";
        Map<String, String> map = xmlToMap(xml);
        System.out.println(map);
    }

    public static Map<String, String> xmlToMap(String xml) throws Exception {
        Map<String, String> map = new HashMap<>();
        SAXReader reader = new SAXReader();
        Document document = reader.read(new StringReader(xml));
        Element root = document.getRootElement().element("object");
        for (Element element : root.elements("void")) {
            Element keyElement = element.element("string");
            Element valueElement = element.elements().get(1);
            String key = keyElement.getText();
            String value = valueElement == null ? null : valueElement.getText();
            map.put(key, value);
        }
        return map;
    }
}

该代码使用Dom4j库解析XML，并将其转换为Map对象。输出结果为:

{att_20160719180419281NEk9=cx, att_20160511094248589ZKYq=cnmm, att_20161018153614188aTus=zsx;fj, att_20160422110906494XuEf=null, att_20160511130210612UULE=fjyxapp;jjgjapp;wx;jd;dxjg;tb;wsjy, att_20160719180542840LnFm=, att_20160511130025203ssle=zdgsszta, att_20160810131359346N0ra=szjys, att_20160511130031927equg=, att_20160422110456036qp7Y=null, att_20160422110543585f7iI=cpjbxx}