QLExpress的基本语法

1、操作符和java对象操作

普通java语法

//支持 +,-,*,/,<,>,<=,>=,==,!=,<>【等同于!=】,%,mod【取模等同于%】,++,--,&&，||
//in【类似sql】,like【类似sql】,&&,||,!,等操作符
//and、or 和java里面的&& || 等价
//支持for，break、continue、if then else 等标准的程序控制逻辑
n=10;
sum=0；
for(i=0;i<n;i++){
sum=sum+i;
}
return sum;
 


//逻辑三元操作
a=1;
b=2;
max = a>b?a:b;

java的对象操作

import com.ql.util.express.test.OrderQuery;
//系统自动会import java.lang.*,import java.util.*;


query = new OrderQuery();//创建class实例,会根据classLoader信息，自动补全类路径
query.setCreateDate(new Date());//设置属性
query.buyer = "张三";//调用属性,默认会转化为setBuyer("张三")
result = bizOrderDAO.query(query);//调用bean对象的方法
System.out.println(result.getId());//静态方法
 

提醒：不支持的java语法

• 不支持try{}catch{}
• 不支持java8的lambda表达式
• 不支持for循环集合操作for (GRCRouteLineResultDTO item : list)
• 弱类型语言，请不要定义类型声明

int a = 10; 
//-》转化后的逻辑
a=10;


FocFulfillDecisionReqDTO reqDTO = param.getReqDTO();
//-》转化后的逻辑
reqDTO = param.getReqDTO();

//数组遍历
for(GRCRouteLineResultDTO item : list) {
}
//-》转化后的逻辑
for(i=0;i<list.size();i++){
item = list.get(i);
}

//map遍历
for(String key : map.keySet()) {
  System.out.println(map.get(key));
}
//-》转化后的逻辑
  keySet = map.keySet();
  objArr = keySet.toArray();
  for (i=0;i<objArr.length;i++) {
  key = objArr[i];
   System.out.println(map.get(key));
  }
  

2、脚本中定义function

function add(int a,int b){
  return a+b;
};

function sub(int a,int b){
  return a - b;
};

a=10;
return add(a,4) + sub(a,9);
 

3、扩展操作符：Operator

替换if then else 等关键字

runner.addOperatorWithAlias("如果", "if",null);
runner.addOperatorWithAlias("则", "then",null);
runner.addOperatorWithAlias("否则", "else",null);

exp = "如果  (语文+数学+英语>270) 则 {return 1;} 否则 {return 0;}";
DefaultContext<String, Object> context = new DefaultContext<String, Object>();
runner.execute(exp,context,null,false,false,null);

如何自定义Operator

//定义一个继承自com.ql.util.express.Operator的操作符
public class JoinOperator extends Operator{
    public Object executeInner(Object[] list) throws Exception {
        Object opdata1 = list[0];
        Object opdata2 = list[1];
        if(opdata1 instanceof java.util.List){
            ((java.util.List)opdata1).add(opdata2);
            return opdata1;
        }else{
            java.util.List result = new java.util.ArrayList();
            result.add(opdata1);
            result.add(opdata2);
            return result;                
        }
    }
}

如何使用Operator

//(1)addOperator
ExpressRunner runner = new ExpressRunner();
DefaultContext<String, Object> context = new DefaultContext<String, Object>();
runner.addOperator("join",new JoinOperator());
Object r = runner.execute("1 join 2 join 3", context, null, false, false);
System.out.println(r);
//返回结果  [1, 2, 3]

//(2)replaceOperator
ExpressRunner runner = new ExpressRunner();
DefaultContext<String, Object> context = new DefaultContext<String, Object>();
runner.replaceOperator("+",new JoinOperator());
Object r = runner.execute("1 + 2 + 3", context, null, false, false);
System.out.println(r);
//返回结果  [1, 2, 3]

//(3)addFunction
ExpressRunner runner = new ExpressRunner();
DefaultContext<String, Object> context = new DefaultContext<String, Object>();
runner.addFunction("join",new JoinOperator());
Object r = runner.execute("join(1,2,3)", context, null, false, false);
System.out.println(r);
//返回结果  [1, 2, 3]

4、绑定java类或者对象的method

addFunctionOfClassMethod+addFunctionOfServiceMethod

public class BeanExample {
    public static String upper(String abc) {
        return abc.toUpperCase();
    }
    public boolean anyContains(String str, String searchStr) {

        char[] s = str.toCharArray();
        for (char c : s) {
            if (searchStr.contains(c+"")) {
                return true;
            }
        }
        return false;
    }
}

runner.addFunctionOfClassMethod("取绝对值", Math.class.getName(), "abs",
                new String[] { "double" }, null);
runner.addFunctionOfClassMethod("转换为大写", BeanExample.class.getName(),
                "upper", new String[] { "String" }, null);

runner.addFunctionOfServiceMethod("打印", System.out, "println",new String[] { "String" }, null);
runner.addFunctionOfServiceMethod("contains", new BeanExample(), "anyContains",
            new Class[] { String.class, String.class }, null);

String exp = “取绝对值(-100);转换为大写(\"hello world\");打印(\"你好吗？\")；contains("helloworld",\"aeiou\")”;
runner.execute(exp, context, null, false, false);

## 5、macro 宏定义

runner.addMacro("计算平均成绩", "(语文+数学+英语)/3.0");
runner.addMacro("是否优秀", "计算平均成绩>90");
IExpressContext<String, Object> context =new DefaultContext<String, Object>();
context.put("语文", 88);
context.put("数学", 99);
context.put("英语", 95);
Object result = runner.execute("是否优秀", context, null, false, false);
System.out.println(r);
//返回结果true

## 6、编译脚本，查询外部需要定义的变量和函数。
注意以下脚本int和没有int的区别

String express = "int 平均分 = (语文+数学+英语+综合考试.科目2)/4.0;return 平均分";
ExpressRunner runner = new ExpressRunner(true,true);
String[] names = runner.getOutVarNames(express);
for(String s:names){
 System.out.println("var : " + s);
}

//输出结果：

var : 数学
var : 综合考试
var : 英语
var : 语文

7、关于不定参数的使用

    @Test
    public void testMethodReplace() throws Exception {
        ExpressRunner runner = new ExpressRunner();
        IExpressContext<String,Object> expressContext = new DefaultContext<String,Object>();
        runner.addFunctionOfServiceMethod("getTemplate", this, "getTemplate", new Class[]{Object[].class}, null);

        //(1)默认的不定参数可以使用数组来代替
        Object r = runner.execute("getTemplate([11,'22',33L,true])", expressContext, null,false, false);
        System.out.println(r);
        //(2)像java一样,支持函数动态参数调用,需要打开以下全局开关,否则以下调用会失败
        DynamicParamsUtil.supportDynamicParams = true;
        r = runner.execute("getTemplate(11,'22',33L,true)", expressContext, null,false, false);
        System.out.println(r);
    }
    //等价于getTemplate(Object[] params)
    public Object getTemplate(Object... params) throws Exception{
        String result = "";
        for(Object obj:params){
            result = result+obj+",";
        }
        return result;
    }

8、关于集合的快捷写法

    @Test
    public void testSet() throws Exception {
        ExpressRunner runner = new ExpressRunner(false,false);
        DefaultContext<String, Object> context = new DefaultContext<String, Object>();
        String express = "abc = NewMap(1:1,2:2); return abc.get(1) + abc.get(2);";
        Object r = runner.execute(express, context, null, false, false);
        System.out.println(r);
        express = "abc = NewList(1,2,3); return abc.get(1)+abc.get(2)";
        r = runner.execute(express, context, null, false, false);
        System.out.println(r);
        express = "abc = [1,2,3]; return abc[1]+abc[2];";
        r = runner.execute(express, context, null, false, false);
        System.out.println(r);
    }

9、集合的遍历

其实类似java的语法，只是ql不支持for(obj:list){}的语法，只能通过下标访问。

  //遍历ArrayList
  list = new ArrayList();
  list.add("a");
  list.add("b");
  for (i=0;i<list.size();i++) {
  obj = list.get(i);
   System.out.println(obj);
  }
  

  //遍历map
  map = new HashMap();
  map.put("a", "a_value");
  map.put("b", "b_value");
  keySet = map.keySet();
  objArr = keySet.toArray();
  for (i=0;i<objArr.length;i++) {
  key = objArr[i];
   System.out.println(map.get(key));
  }
  

10、布尔表达式的判断输出

如何判断整个表达式的返回结果，并且输出其中的逻辑子节点

( 2 < 1 ) and (违规天数 < 90 or 虚假交易扣分 < 12)

//简单初始化即可
runner.getOperatorFactory().getOperator("<").setErrorInfo("$1 < $2 = false");
runner.getOperatorFactory().getOperator(">").setErrorInfo("$1 > $2 = false");

runner.setShortCircuit(false);//可以设置是否启用逻辑短路，默认为true

详细case：
https://github.com/alibaba/QLExpress/blob/master/src/test/java/com/ql/util/express/test/logic/SimpleShortCircuitLogicTest.java