java 8 spring spEL可重复绑定减慢每次迭代

Question

我正在使用spEL 4.0.0.RELEASE将http参数绑定到java对象.我多次使用表达式解析器时会注意到一些奇怪的问题:每次调用都需要更多的时间(常量).这只发生在java 8上.在java 7上都可以.

这是示例代码:

package ru.tersys.test;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;

import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

public class Test {

public static void main(String[] args) {

    Test instance = new Test();

    Table t = new Table();
    Column c = new Column();
    t.getColumns().add(c);      

    int counter = 10;       
    while (counter-- > 0)
    {
        instance.doTest("t", t);
    }
}

ExpressionParser parser = new SpelExpressionParser();
StandardEvaluationContext context = new StandardEvaluationContext();

public void doTest(String prefix, Object obj)
{
    Date d = Calendar.getInstance().getTime();
     int counter = 0;       
        String el = "t.columns[0].name";         

        context.setVariable(prefix, obj);
        String prefixWithDot = prefix + ".";

        int count = 400;

        while (count -- > 0)
        {
            if (el.startsWith(prefixWithDot))
            {
                parser.parseExpression("#"+el).setValue(context, "testColumnName");
                counter++;
            }
        }           
System.out.println("bind duration sec =  " + (Calendar.getInstance().getTime().getTime() - d.getTime())/1000 + " param count = " + counter);        

}




static class Table
{
    public Table()
    {
        columns = new ArrayList<>();
    }
    public ArrayList<Column> getColumns() {
        return columns;
    }
    public void setColumns(ArrayList<Column> columns) {
        this.columns = columns;
    }
    private ArrayList<Column> columns;

}

static class Column
{
    public Column()
    {

    }
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

}

jdk 8输出:

bind duration sec =  1 param count = 400
bind duration sec =  3 param count = 400
bind duration sec =  5 param count = 400
bind duration sec =  7 param count = 400
bind duration sec =  9 param count = 400
bind duration sec =  12 param count = 400
bind duration sec =  14 param count = 400
bind duration sec =  16 param count = 400
bind duration sec =  19 param count = 400
bind duration sec =  22 param count = 400

java 7输出:

bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400
bind duration sec =  0 param count = 400

这个bug还是功能？有没有解决方法？

Answer 1

它可能与此JIRA 问题“Java 1.7.0_51 上 SerializedTypeWrapper 的性能问题”有关，该问题已在 4.0.1 中修复。