java多线程查询_java多线程查询

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由于最近工作遇到性能问题，尝试研究用多线程来实现，结果速度快了好几倍

下面是多线程查询的部分代码，提供给大家参考下：

线程类：

带返回值的类要实现Callable接口，具体业务逻辑没有实现，只是写了个空方法在里面

package com.sanfy.demo.thread;

import java.util.List;

import java.util.Map;

import java.util.concurrent.Callable;

import com.sanfy.demo.model.WorkLoad;

public class QueryThread implements Callable> {

private List workLoads;

private WorkLoadService workLoadService;

private Map parameters;

private List dates;

private int begin;

private int end;

public QueryThread(Map parameters,List dates, int begin, int end,WorkLoadService workLoadService) {

super();

this.parameters = parameters;

this.dates = dates;

this.begin = begin;

this.end = end;

this.workLoadService=workLoadService;

}

/**

* @return Map

* @see java.lang.Callable#call()

*/

@Override

public Map call() {

for (int i = begin; i < end; i++) {

queryListByMap(dates.get(i));

}

return workLoads;

}

/**

* 查询方法

*

* @param date 日期

* @param i i

*/

private void queryListByMap(String date) {

//具体的查询

workLoads=workLoadService.queryList(parameters,date);

}

public List getWorkLoads() {

return workLoads;

}

public void setWorkLoads(List workLoads) {

this.workLoads = workLoads;

}

public WorkLoadService getWorkLoadService() {

return workLoadService;

}

public void setWorkLoadService(WorkLoadService workLoadService) {

this.workLoadService = workLoadService;

}

public Map getParameters() {

return parameters;

}

public void setParameters(Map parameters) {

this.parameters = parameters;

}

public List getDates() {

return dates;

}

public void setDates(List dates) {

this.dates = dates;

}

public int getBegin() {

return begin;

}

public void setBegin(int begin) {

this.begin = begin;

}

public int getEnd() {

return end;

}

public void setEnd(int end) {

this.end = end;

}

}

serive调用线程类来实现多线程查询：

package com.sanfy.demo.thread;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import com.sanfy.demo.model.WorkLoad;

public class QuerySerivce {

private WorkLoadService workLoadService;

public List queryListsByMap(String sqlCode, Map parameters) throws Exception {

List workLoads=new ArrayList();

long startTime = System.currentTimeMillis();

List dates = DateUtil.getCurrentInYear(parameters.get("startDate").toString(), 12);

if (dates != null && dates.size() > 0) {

int len = dates.size();

// 创建线程的个数

int count = len % 2 == 0 ? len / 2: (len / 2) + 1;

// 创建线程池数量

ExecutorService pool = Executors.newFixedThreadPool(count);

List>> tasks = new ArrayList>>();

for (int i = 0; i < count; i++) {

// 每个线程负责插入数据的开始位置

int start = i * 2;

// 每个线程负责插入数据的结束位置

int end = i == count - 1 ? i * 2 + (len - i * 2) : i* 2+ 2;

Map parametersClone = new HashMap();

parametersClone.putAll(parameters);

// 线程返回值

Callable> task = new QueryThread(parametersClone, sqlCode, dates, start, end,workLoadService);

tasks.add(task);

}

// 执行线程

List>> futures = pool.invokeAll(tasks);

// 处理线程返回结果

if (futures != null && futures.size() > 0) {

for (Future> future : futures) {

workLoads.addAll(future.get());

}

}

// 关闭线程池

pool.shutdown();

}

long endTime = System.currentTimeMillis();

logger.info("多个情况报表查询总共花了:" + (endTime - startTime) / 1000 + "秒时间!");

return workLoads;

}

}

后续会补上多线程批量保存与android多线程支持断点续传下载的内容

由于是实际项目，所以把具体的内容删除了，直接修改的，供大家参考下

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