hashMap里有键值对 Draft_dwg=abc、 Draft_pdf=cdf、Draft_wmf=gph
我现在如何把hashmap中的key得到,并且拼接成字符串的形式,比如字符串1得到 “Draft_dwg, Draft_pdf, Draft_wmf”
字符串2得到"abc,cdf,gph" 因为这两个字符串要插入到sql语句,insert into flat (字符串1) values (字符串2)
我现在如何把hashmap中的key得到,并且拼接成字符串的形式,比如字符串1得到 “Draft_dwg, Draft_pdf, Draft_wmf”
字符串2得到"abc,cdf,gph" 因为这两个字符串要插入到sql语句,insert into flat (字符串1) values (字符串2)
Iterator iter = map.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry entry = (Map.Entry) iter.next();
Object key = entry.getKey();
Object val = entry.getValue();
}
public static void main(String[] args) {
LinkedHashMap<String, String> map = new LinkedHashMap<>();
map.put("Draft_dwg", "abc");
map.put("Draft_pdf", "cdf");
map.put("Draft_wmf", "gph");
System.out.println(createInsertSQL(map, "flat"));
}public static String createInsertSQL(Map<String, String> map, String table) {
StringBuilder keys = new StringBuilder();
StringBuilder values = new StringBuilder();
boolean first = true;
for (Entry<String, String> entry : map.entrySet()) {
if (!first) {
keys.append(", ");
values.append(", ");
}
first = false;
keys.append(entry.getKey());
values.append("\"" + entry.getValue() + "\"");
}
return "insert into " + table + " (" + keys + ") values (" + values + ")";
}
map.put("Draft_dwg", "abc");
map.put("Draft_pdf", "cdf");
map.put("Draft_wmf", "gph");
StringBuffer cols = new StringBuffer();
StringBuffer vals = new StringBuffer();
boolean first = true; for (String key : map.keySet())
{
if (!first)
{
cols.append(", ");
vals.append(", ");
}
first = false;
cols.append(key);
vals.append("'" + map.get(key) + "'");
}
System.out.println("insert into flat (" + cols + ") values (" + vals+ ")");
Map<String, String> map = new HashMap<String, String>();
map.put("Draft_dwg", "abc");
map.put("Draft_pdf", "cdf");
map.put("Draft_wmf", "gph");
Set<String> keys = map.keySet() ;
Collection<String> values = map.values() ;
System.out.println( keys );
System.out.println( values );