一个map问题

Question

String[] arr = (String[]) map.get("a");
有什么错误?为什么出现异常

Answer 1

没头没尾的
你要做什么
map里面"a"位置放的是String[]吗？

Answer 2

我把2个类都贴上,大家研究下:
public class BiaoOne {
String zuhao;
String qingqiuleixing;
int    xuhao;
int    zixuhao;
String biaozhun;
String guishu;
String xunhuan;
int xunhuanxianggeshu;

BiaoOne(){

}

BiaoOne(String s1, String s2, int i1, int i2, String s3,
String s4, String s5, int i3){
this.zuhao = s1;
this.qingqiuleixing = s2;
this.xuhao = i1;
this.zixuhao = i2;
this.biaozhun = s3;
this.guishu = s4;
this.xunhuan = s5;
this.xunhuanxianggeshu = i3;
} public String getBiaozhun() {
return biaozhun;
} public void setBiaozhun(String biaozhun) {
this.biaozhun = biaozhun;
} public String getGuishu() {
return guishu;
} public void setGuishu(String guishu) {
this.guishu = guishu;
} public String getQingqiuleixing() {
return qingqiuleixing;
} public void setQingqiuleixing(String qingqiuleixing) {
this.qingqiuleixing = qingqiuleixing;
} public int getXuhao() {
return xuhao;
} public void setXuhao(int xuhao) {
this.xuhao = xuhao;
} public String getXunhuan() {
return xunhuan;
} public void setXunhuan(String xunhuan) {
this.xunhuan = xunhuan;
} public int getXunhuanxianggeshu() {
return xunhuanxianggeshu;
} public void setXunhuanxianggeshu(int xunhuanxianggeshu) {
this.xunhuanxianggeshu = xunhuanxianggeshu;
} public int getZixuhao() {
return zixuhao;
} public void setZixuhao(int zixuhao) {
this.zixuhao = zixuhao;
} public String getZuhao() {
return zuhao;
} public void setZuhao(String zuhao) {
this.zuhao = zuhao;
}


}///////////////////////////////////////////////////////////////////////////////////
import java.util.Map;
import java.util.TreeMap;
import java.util.ArrayList;
import java.util.Iterator;public class Test1 {
Map map = new TreeMap();
Test1()
{
map.put("package.head.requesttype","001");
map.put("package.head.user","PICC");
map.put("package.head.code","12345678");
map.put("package.body.policyno","00PICC1234567890");
map.put("package.body.startdate","20070101");
map.put("package.body.insured","张三");
map.put("package.third.driverlist.driver.name","李1");
map.put("package.third.driverlist.driver.age","20");
map.put("package.third.driverlist.driver.name","李2");
map.put("package.third.driverlist.driver.age","21");
map.put("package.third.driverlist.driver.name","李3");
map.put("package.third.driverlist.driver.age","22");
map.put("package.third.date","19990909");
}

public String adapter(Map map)
{
ArrayList arraylist = new ArrayList();
BiaoOne biao1 = new BiaoOne("1","7000",1,0,"package.head.requesttype","head","n",0);
arraylist.add(biao1);
BiaoOne biao2 = new BiaoOne("1","7000",2,0,"package.head.user","head","n",0);
arraylist.add(biao2);
BiaoOne biao3 = new BiaoOne("1","7000",3,0,"package.head.code","head","n",0);
arraylist.add(biao3);
BiaoOne biao4 = new BiaoOne("1","7000",4,0,"package.body.policyno","body","n",0);
arraylist.add(biao4);
BiaoOne biao5 = new BiaoOne("1","7000",5,0,"package.body.startdate","body","n",0);
arraylist.add(biao5);
BiaoOne biao6 = new BiaoOne("1","7000",6,0,"package.body.insured","body","n",0);
arraylist.add(biao6);
BiaoOne biao7 = new BiaoOne("1","7000",7,0,"package.third.driverlist.driver","","y",2);
arraylist.add(biao7);
BiaoOne biao8 = new BiaoOne("1","7000",7,1,"package.third.driverlist.driver.name","","n",0);
arraylist.add(biao8);
BiaoOne biao9 = new BiaoOne("1","7000",7,2,"package.third.driverlist.driver.age","","n",0);
arraylist.add(biao9);
BiaoOne biao10 = new BiaoOne("1","7000",8,0,"package.third.date","third","n",0);
arraylist.add(biao10);
BiaoOne biao = new BiaoOne();
String outstr = "";                                      //最后返回的字符串
int where = 0;                                           //解码方案:0字符串 1非标准XML 2标准XML
if(where == 0){

Iterator iterator = arraylist.iterator();
while (iterator.hasNext()) {                    //遍历
biao = (BiaoOne) iterator.next();
if (biao.xunhuan.equalsIgnoreCase("n")) {        //非循环项
outstr = outstr + (String)(map.get(biao.getBiaozhun()) + "|");
} 
else {                                          //循环项
int number = biao.getXunhuanxianggeshu();   //循环项个数
String[] bigarr = new String[100];          //定义一个临时大数组用来拼接循环项
String[] arrValue = null;                   //转载循环字段的多个值
for (int i = 0; i < number; i++) {          //将循环字段的值按一定顺序提出放到大数组中
biao = (BiaoOne) iterator.next();
arrValue = (String[]) (map.get(biao.getBiaozhun()));         for (int j = 0; j < arrValue.length; j++) {
         bigarr[j * number + 1] = arrValue[j];
        }
}
for (int i = 0; i < bigarr.length; i++) {
outstr = outstr + bigarr[i];
}
}
}//whlie

}//if
System.out.println(outstr);
return "";
} public static void main(String[] args) {
Test1 test1 = new Test1();
test1.adapter(test1.map);
}
}

Answer 3

Iterator iterator = arraylist.iterator();
                while (iterator.hasNext()) {                    //遍历
                biao = (BiaoOne) iterator.next();
                if (biao.xunhuan.equalsIgnoreCase("n")) {        //非循环项
                    outstr = outstr + (String)(map.get(biao.getBiaozhun()) + "|");
                } 
                else {                                          //循环项
                    int number = biao.getXunhuanxianggeshu();   //循环项个数
                    String[] bigarr = new String[100];          //定义一个临时大数组用来拼接循环项
                    String[] arrValue = new String[number];                   //转载循环字段的多个值
                    for (int i = 0; i < number; i++) {          //将循环字段的值按一定顺序提出放到大数组中
                        biao = (BiaoOne) iterator.next();
                        arrValue[i] = (String) (map.get(biao.getBiaozhun()));                        for (int j = 0; j < arrValue.length; j++) {
                            bigarr[j * number + 1] = arrValue[j];
                        }
                    }
                    for (int i = 0; i < bigarr.length; i++) {
                        outstr = outstr + bigarr[i];
                    }
                }
            }//whlie这样修改一下，就可以跑通了。至于具体的细节。我也没时间，今天周末，我要回家了。

Answer 4

你的错误在于 ： (map.get(biao.getBiaozhun()));里面 的对象是 String， 而不是 String[]
.

Answer 5

汗 没看你贴得那么多代码 
不过可以肯定你问题不是出在你说的这句话
我的测试代码
Map map=new HashMap();
String t[]={"1","2"};
map.put( "a",t);
String[] arr = (String[]) map.get("a");
System.out.println(arr[1]);
一切ok如果说出错的话就是你map.put的时候没有放入一个数组 导致cast错误
接分

Answer 6

唉
lz呀lz，本来我可以拿分的，结果......我都问你了“map里面"a"位置放的是String[]吗？”
你也回答了“是string,怎么会是[]呢?”怎么还要给别人分呢？

Answer 7

听说有100分　哈哈　
下面我的分析首先取出这个("1","7000",7,0,"package.third.driverlist.driver","","y",2);xunhuan=y所以进入else块然后取下面一个信息("1","7000",7,1,"package.third.driverlist.driver.name","","n",0);通过package.third.driverlist.driver.name去取map里的值map里有3个相关值
map.put("package.third.driverlist.driver.name","李1");
map.put("package.third.driverlist.driver.name","李2");
map.put("package.third.driverlist.driver.name","李3");map是key value 
而key是一个set set不能重复你map.size测试下是9而不是14

Answer 8

你这个程序２个错误
1，map设计错误 照你的意思容器不能是map
2,map对应值错误是string而不是String[]解决方案
map.put("package.third.driverlist.driver.name","李1");
map.put("package.third.driverlist.driver.name","李2");
map.put("package.third.driverlist.driver.name","李3");
改称
map.put("package.third.driverlist.driver.name",{"李1","李1","李1"});

Answer 9

问题解决了,这个MAP不是我写的,里面有一定的问题,另外取出来的确实是一个字符串数组.谢谢大家 给出代码的多给分.我再建个100分的帖子给分.

Answer 10

请到http://community.csdn.net/Expert/topic/5212/5212881.xml?temp=.3915064
留言我给大家分