import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
public class SQLUtils {
public static void main(String[] args) {
Map<String, Object> map = new HashMap<>();
map.put("stuName", "欧可乐");
map.put("stuAge", 20);
map.put("stuSex", "男");
map.put("Key_stuId", "ASDF");
map.put("Key_stuSex", "ASDF");
try {
System.out.println(getSql("table_name", "delete", map, false, ""));
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 动态组装 简单sql语法
*
* @param tableName 表名
* @param operation 操作标识符 select|delete|update ,默认为 select
* @param mapData 数据的map集合
* @param useMySQL true|false , false 为使用动态组装SQL，true为使用自已的sql
* @param mySql 自已的sql
* 注意：update 这里，where xxx = xxx ,的时候，mapData 里的键必须要有 Key_ 前缀（其他的 并不影响到）
* @return
* @throws Exception
*/
public static String getSql(String tableName, String operation, Map<?, ?> mapData, boolean useMySQL, String mySql) throws Exception {
String sql = null;
// 使用组装sql的功能
if (!useMySQL) {
if (!(tableName != null && !tableName.equals("") && tableName.length() > 0)) {
throw new Exception(" 参数 tableName 的值为空！");
} else if (!(mapData != null && !mapData.equals("") && mapData.size() > 0)) {
throw new Exception(" 参数 mapData 的值为空！");
}
// 操作标识 默认为 select
String operations = "select";
String condition = " a.* from " + tableName + " a where ";
if (operation != null && !operation.equals("")) {
if (operation.equals("update") || operation.equals("UPDATE")) {
operations = "update";
condition = " " + tableName + " a set ";
} else if (operation.equals("delete") || operation.equals("DELETE")) {
operations = "delete";
condition = " from " + tableName + " a where ";
} else if (operation.equals("insert") || operation.equals("INSERT")) {
operations = "insert";
condition = " into " + tableName + " (";
String link = "";
Iterator<?> iterator = mapData.keySet().iterator();
while (iterator.hasNext()) {
String next = (String) iterator.next();
condition += link + next;
link = ",";
}
condition += ") values( ";
}
}
String value = "";
String link = "";
String keyValueOperations = " where ";
Iterator<? extends Map.Entry<?, ?>> iterator = mapData.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry<?, ?> next = iterator.next();
if (next.getValue() instanceof String) {
value = "'" + next.getValue() + "'";
} else {
value = "" + next.getValue() + "";
}
if (next.getKey().toString().lastIndexOf("Key_") == -1) {
if (!operations.equals("insert")) {
if (operations.equals("select") || operations.equals("delete")) {
condition += link + "a." + next.getKey();
condition += "=" + value;
link = " and ";
} else {
condition += link + "a." + next.getKey();
condition += "=" + value;
link = ",";
}
} else {
condition += link + value;
link = ",";
}
} else {
continue;
}
}
// 组装 insert sql 的结尾
if (operations.equals("insert")) {
condition += ")";
} else if (operations.equals("update")) { // 组装 update sql 的结尾
condition += " where ";
String and = "";
Iterator<? extends Map.Entry<?, ?>> iterator1 = mapData.entrySet().iterator();
while (iterator1.hasNext()) {
Map.Entry<?, ?> next = iterator1.next();
if (next.getValue() instanceof String) {
value = "'" + next.getValue() + "'";
} else {
value = "" + next.getValue() + "";
}
String key = next.getKey().toString();
if (key.lastIndexOf("Key_") != -1) {
key = key.substring(key.indexOf("Key_") + 4, key.length());
condition += and + "a." + key + "=" + value;
and = " and ";
}
}
}
sql = operations + condition;
} else { // 不使用组装sql的功能
sql = mySql;
}
return sql;
}
}
