对sql的查询语句做成对象式，简单实现。Where部分
package net.zz.zjf.plugin;import java.lang.reflect.Array;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Created by ZaoSheng on 2015/8/5.
*/
public class Where implements SQLParams{
//用于存放第一个条件的名
private String first = null;
/*这里存放所有的where需要用到的东西。wheres的key是property名,value主要分为三部分
*value主要分为三部分，value用来存放property的值，在BETWEEN的情况下value是数组
*数组长度为2。value存放AndOr,value存放具体的where操作，比如 ">",">=","like","in"
*等操作。
*/
private Map wheres = new HashMap();
//这个对象用来存放具体的属性值attrs的key是sql中":property"中的"property",value是对应的值
private Map attrs = new HashMap();
//这个集合不一定有值，在执行toFormatSQL方法后才会有值。存放的值依次对应sql中的第几个"?"
private List paras = new ArrayList();
public Where() {
}
public Where(String propertyName, Object value, AndOr andor, Restriction restriction) {
first = propertyName;
add(propertyName, value, andor, restriction);
}
public Where(String propertyName, Object value, AndOr andor) {
this(propertyName, value, andor, Restriction.EQ);
}
public Where(String propertyName, Object value, Restriction restriction) {
this(propertyName, value, AndOr.NUL, restriction);
}
public Where(String propertyName, Object value) {
this(propertyName, value, Restriction.EQ);
}
public Map getWheres() {
return wheres;
}
public Map getAttrs() {
return attrs;
}
public List getParas() {
return paras;
}
public Where and(String propertyName, Object value, Restriction restriction) {
add(propertyName, value, AndOr.AND, restriction);
return this;
}
public Where and(String propertyName, Object value) {
return and(propertyName, value, Restriction.EQ);
}
public Where or(String propertyName, Object value, Restriction restriction) {
add(propertyName, value, AndOr.OR, restriction);
return this;
}
public Where or(String propertyName, Object value) {
return or(propertyName, value, Restriction.EQ);
}
protected void add(String key, Object value, AndOr andor, Restriction restriction) {
if (null == value || "".equals(value)) {
if (key.equals(first))
{
first = null;
}
wheres.remove(key);
} else {
wheres.put(key, new Object[]{value, andor, restriction});
}
}
public String toSQL() {
if (wheres.isEmpty()) return "";
StringBuilder sb = new StringBuilder();
if (null != first)setSql(first, wheres.get(first), sb );
for (String key : wheres.keySet()) {
if (key.equals(first))continue;
Object[] objects = wheres.get(key);
setSql(key, objects, sb);
}
return sb.toString();
}
/**
*这个方法之所以提取出来是因为能更好的在多个地方引用(应该用代码重构的方式来讲的,可惜我不会讲).
*/
private void setSql(String key, Object[] objects, StringBuilder sb)
{
AndOr andOr = (AndOr) objects;
Restriction restriction = (Restriction)objects;
switch (restriction) {
case LIKE:
case LLIKE:
case RLIKE:
sb.append(andOr.toMatchString(key, "like :" + key));
attrs.put(key, restriction.toMatchString(objects.toString()));
break;
case NULL:
case NOTNULL:
sb.append(andOr.toMatchString("", restriction.toMatchString(key)));
break;
case BETWEEN:
sb.append(andOr.toMatchString(key, restriction.toMatchString(key)));
Object[] value = (Object[]) objects;
attrs.put(String.format("%s1", key),value);
attrs.put(String.format("%s2", key),value);
break;
default:
sb.append(andOr.toMatchString(key, restriction.toMatchString(key)));
attrs.put(key, objects);
}
}
@Override
public String toFormatSQL() {
returntoFormatSQL(toSQL(), attrs, paras);
}
/**
* @param whereSQL
* @param attrs
* @param values
* @return
*/
public static String toFormatSQL(String whereSQL, Map attrs, List values) {
Matcher matcher = Pattern.compile(":(\\w+)").matcher(whereSQL);
String rexp = null;
while (matcher.find()) {
String group = matcher.group(1);
Object ov = attrs.get(group);
if (ov instanceof List) {
StringBuilder sb = new StringBuilder();
List vs = (List) ov;
for (Object v : vs) {
sb.append("?,");
values.add(v);
}
sb.deleteCharAt(sb.length() - 1);
rexp = sb.toString();
} else {
values.add(ov);
rexp = "?";
}
whereSQL = whereSQL.replace(String.format(":%s", group), rexp);
}
return whereSQL;
}
@Override
public String toString() {
return toFormatSQL();
}
public static void main(String[] args) {
Calendar c = new GregorianCalendar();
Where where = new Where("name", "张三");
where.or("class", 2);
where.and("sex", true);
where.and("age", new Integer[]{1,10}, Restriction.BETWEEN);
List ids = new ArrayList();
ids.add(4);
ids.add(3);
where.and("id", ids, Restriction.IN);
System.out.println(where.toString());
for (Object value :where.getParas())
{
System.out.print(String.format("%s ", value));
}
}
}
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