OGNL使用例子

1. 导入相关的jar包

   		<dependency>
   			<groupId>ognl</groupId>
   			<artifactId>ognl</artifactId>
   			<version>3.3.4</version>
   		</dependency>
   
   

2. 使用例子代码

   package com.lomi.ognl;
   
   import cn.hutool.core.bean.BeanUtil;
   import cn.hutool.json.JSON;
   import cn.hutool.json.JSONUtil;
   import com.lomi.entity.Goods;
   import com.lomi.entity.out.GoodsOut;
   import ognl.Ognl;
   import ognl.OgnlContext;
   import ognl.OgnlException;
   import org.junit.Test;
   
   import java.util.Arrays;
   import java.util.Map;
   
   /**
    *
    *  ognl 对象图导航语言，可以通过表达式从Java对象，json ，map中获取到值
    *  如果表达式取到不存在的属性值会报错
    *
    * @author ZHANGYUKUN
    */
   public class OGNLTest {
   
   
       public static String  staticValue = "静态属性";
       public static String getStaticValue() {
           return staticValue;
       }
   
       private String name = "张三丰";
       public String getName() {
           return name;
       }
       public void setName(String name) {
           this.name = name;
       }
   
       /**
        * 使用 # 是区_value里面的值,没有#取的root里面的值
        *
        * @throws OgnlException
        */
       @Test
       public void t1() throws OgnlException {
           //this就是root节点
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext(this);
           context.put("goods",Goods.randomGoods());
   
           Object ognlName1 = Ognl.parseExpression("#goods.name");
           Object ognlName2 = Ognl.parseExpression("name");
   
           Object name1 = Ognl.getValue( ognlName1, context, context.getRoot());
           Object name2 = Ognl.getValue( ognlName2, context, context.getRoot());
   
           System.out.println("获取到的name1："  + name1);
           System.out.println("获取到的name2："  + name2);
   
       }
   
       /**
        *   context 里面的值的时候，可以任意传入 context ，context只是一个map 而已，不一定非要用  OGNLContext的 _value 属性
        * @throws OgnlException
        */
       @Test
       public void t2() throws OgnlException {
           Map<String, Object> objectMap = BeanUtil.beanToMap(Goods.randomGoods());
   
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext( objectMap );
   
   
           //并且这个 context 不一定需要是 OgnlContext里面的 _value
           Object ognl = Ognl.parseExpression("#id");
           Object value2 = Ognl.getValue(ognl, objectMap  ,context.getRoot());
           System.out.println(value2);
       }
   
   
       /**
        *  如果是Java对象 取不存在的属性会报错
        * @throws OgnlException
        */
       @Test
       public void t3() throws OgnlException {
           Map<String, Object> objectMap = BeanUtil.beanToMap(Goods.randomGoods());
   
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext( objectMap );
   
   
           //并且这个 context 不一定需要是 OgnlContext里面的 _value
           Object ognl = Ognl.parseExpression("#id.name");
           Object value2 = Ognl.getValue(ognl, objectMap  ,context.getRoot());
           System.out.println(value2);
       }
   
   
       /**
        *  map取不到不会报错，但是继续取下级就会报错
        * @throws OgnlException
        */
       @Test
       public void t4() throws OgnlException {
           Map<String, Object> objectMap = BeanUtil.beanToMap(Goods.randomGoods());
   
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext( objectMap );
   
   
           //并且这个 context 不一定需要是 OgnlContext里面的 _value
           Object ognl = Ognl.parseExpression("#name2");
           Object value2 = Ognl.getValue(ognl, objectMap  ,context.getRoot());
           System.out.println(value2);
       }
   
   
   
       /**
        * 获取数组的值
        * @throws OgnlException
        */
       @Test
       public void t5() throws OgnlException {
           Map<String, Object> objectMap = BeanUtil.beanToMap(Goods.randomGoods());
           objectMap.put("list", Arrays.asList(  Goods.randomGoods(),Goods.randomGoods(),Goods.randomGoods() ));
   
           System.out.println(JSONUtil.formatJsonStr( JSONUtil.toJsonStr(  objectMap ) ));
   
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext( objectMap );
   
   
           //并且这个 context 不一定需要是 OgnlContext里面的 _value
           Object ognl = Ognl.parseExpression("#list[0].name");
           Object value1 = Ognl.getValue(ognl, objectMap  ,context.getRoot());
           System.out.println(value1);
   
   
           //投影语法，取到把 集合里面的某个属性取出来构成一个集合
           Object ognl2 = Ognl.parseExpression("#list.{name}");
           Object value2 = Ognl.getValue(ognl2, objectMap  ,context.getRoot());
           System.out.println(value2);
   
   
           //筛选
           Object ognl3 = Ognl.parseExpression("#list.{? stock>2000}");
           Object value3 = Ognl.getValue(ognl3, objectMap  ,context.getRoot());
           System.out.println(value3);
   
   
           //筛选以后取第一个
           Object ognl4 = Ognl.parseExpression("#list.{^ stock>2000}");
           Object value4 = Ognl.getValue(ognl4, objectMap  ,context.getRoot());
           System.out.println(value4);
   
           //筛选以后取最后一个
           Object ognl5 = Ognl.parseExpression("#list.{$ stock>2000}");
           Object value5 = Ognl.getValue(ognl5, objectMap  ,context.getRoot());
           System.out.println(value5);
   
       }
   
   
       /**获取静态值
        * @throws OgnlException
        */
       @Test
       public void t6() throws OgnlException {
           //this就是root节点
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext(this);
   
           Object ognlName1 = Ognl.parseExpression("@com.lomi.ognl.OGNLTest@staticValue");
           Object name1 = Ognl.getValue( ognlName1, context, context.getRoot());
   
           System.out.println("获取到的name1："  + name1);
       }
   
       /**调用方法
        * @throws OgnlException
        */
       @Test
       public void t7() throws OgnlException {
           //this就是root节点
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext(this);
   
           //调用普通方法
           Object ognlName1 = Ognl.parseExpression("getName()");
           Object name1 = Ognl.getValue( ognlName1, context, context.getRoot());
   
           //调用有参数的方法
           Object ognlName2 = Ognl.parseExpression("setName( '张三' )");
           Object name2 = Ognl.getValue( ognlName2, context, context.getRoot());
   
   
           Object name3 = Ognl.getValue( ognlName1, context, context.getRoot());
   
           //静态方法
           Object name4 = Ognl.getValue( "@com.lomi.ognl.OGNLTest@getStaticValue()", context, context.getRoot());
   
           System.out.println("获取到的name1："  + name1);
           System.out.println("获取到的name2："  + name2);
           System.out.println("获取到的name3："  + name3);
           System.out.println("获取到的name4："  + name4);
       }
   
   
       /**
        * 逗号表达式，每个都执行，获取的值是最后一个
        *
        * @throws OgnlException
        */
       @Test
       public void t8() throws OgnlException {
           //this就是root节点
           OgnlContext context = (OgnlContext) Ognl.createDefaultContext(this);
   
           //调用普通方法
           Object ognlName1 = Ognl.parseExpression("getName(),@com.lomi.ognl.OGNLTest@getStaticValue()");
           Object ognlName2 = Ognl.parseExpression("@com.lomi.ognl.OGNLTest@getStaticValue(),getName()");
           Object name1 = Ognl.getValue( ognlName1, context, context.getRoot());
           Object name2 = Ognl.getValue( ognlName2, context, context.getRoot());
   
           System.out.println("获取到的name1："  + name1);
           System.out.println("获取到的name2："  + name2);
       }
   
   
   
   
   }