我想打印一个数组列表,在该数组列表中它包含哈希映射,我打印在一个文本文件中。在尝试打印文本文件时,它以单行形式打印。我需要单独排队示例:
ArrayList<Object> mainlist= new ArrayList<>();
LinkedHashMap<String, String> hmap = new LinkedHashMap<>();
for (int i=0;i<5;i++)
{
hmap.put("key1", "03-08-2018");
hmap.put("key2", "xyz";
hmap.put("key3", "123");
//ArrayList USed:::
mainlist.add(hmap);
mainlist.add("n");
}
return mainlist;
我以文本文件的形式返回。它只生成一行,但我的输出文本文件中需要单独的行。
文本文件中的预期输出:
[{key1=03-08-2018,key2=xyz,key3=123}
{key1=03-08-2018,key2=xyz,key3=123}
{key1=03-08-2018,key2=xyz,key3=123}
]
文本文件中的实际输出:
[{key1=03-08-2018,key2=xyz,key3=123},{key1=03-08-2018,key2=xyz,key3=123},{key1=03-08-2018,key2=xyz,key3=123}]
有人能帮我摆脱困境吗
感谢您的回复
我测试了你的代码,它对我来说很有效。你是如何将它写入文件的?
我是这样做的:
Path path = Paths.get("/test/outputXXXX.txt");
ArrayList<Object> mainlist= new ArrayList<>();
LinkedHashMap<String, String> hmap = new LinkedHashMap<>();
for (int i=0;i<5;i++)
{
hmap.put("key1", "03-08-2018");
hmap.put("key2", "xyz");
hmap.put("key3", "123");
//ArrayList USed:::
mainlist.add(hmap);
mainlist.add("n");
}
try (BufferedWriter writer = Files.newBufferedWriter(path))
{
writer.write(mainlist.toString());
}
文件中的输出:
[{key1=03-08-2018, key2=xyz, key3=123},
, {key1=03-08-2018, key2=xyz, key3=123},
, {key1=03-08-2018, key2=xyz, key3=123},
, {key1=03-08-2018, key2=xyz, key3=123},
, {key1=03-08-2018, key2=xyz, key3=123},
]
编辑:对不起,我看不出你需要没有逗号的。
你可以这样做:
Path path = Paths.get("/test/outputXXXX.txt");
ArrayList<Object> mainlist= new ArrayList<>();
LinkedHashMap<String, String> hmap = new LinkedHashMap<>();
for (int i=0;i<5;i++)
{
hmap.put("key1", "03-08-2018");
hmap.put("key2", "xyz");
hmap.put("key3", "123");
//ArrayList USed:::
mainlist.add(hmap);
mainlist.add("n");
}
try (BufferedWriter writer = Files.newBufferedWriter(path))
{
writer.write("[");
for (Object o : mainlist) {
writer.write(o.toString());
}
writer.write("]");
}
ArrayList<Object> mainlist= new ArrayList<>();
LinkedHashMap<String, String> hmap = new LinkedHashMap<>();
for (int i=0;i<5;i++)
{
hmap.put("key1", "03-08-2018");
hmap.put("key2", "xyz"); //you missed closing paranthesis here
hmap.put("key3", "123");
//ArrayList USed:::
mainlist.add(hmap);
mainlist.add("n");
}
return mainlist;
您可以在中尝试以下代码:https://www.tutorialspoint.com/compile_java_online.php
import java.util.*;
public class ArrayListExample{
public static void main(String args[]){
ArrayList<Object> mainlist= new ArrayList<>();
LinkedHashMap<String, String> hmap = new LinkedHashMap<>();
int i=0;
for (i=0;i<5;i++) {
hmap.put("key1", "03-08-2018");
hmap.put("key2", "xyz");
hmap.put("key3", "123");
//ArrayList USed:::
mainlist.add(hmap);
mainlist.add("n");
}
System.out.println(mainlist);
return;
}
}
这给出了您的预期输出。希望这对你有帮助。谢谢