redis学习笔记-java操作String类型

package com.naxsu.redis;import static org.junit.Assert.*;import java.util.ArrayList;import java.util.List;import org.junit.Before;import org.junit.Test;import redis.clients.jedis.Jedis;import redis.clients.jedis.exceptions.JedisDataException;/** * 对String类型进行操作 * 为了僻免上面的测试的结果影响到当前测试方法，测试之前先把数据库给清空 */public class StringValuesCommandsTest{Jedis jedis = null;@Beforepublic void before(){jedis = new Jedis("192.168.26.128");jedis.auth("123456");jedis.flushDB();}@Testpublic void flushDB() {jedis.flushDB();// 清空redis}    @Test    public void setAndGet() {    //对key为foo进行赋值        String status = jedis.set("foo", "bar");        //返回OK        assertEquals("OK", status);        //获取key为foo的值        String value = jedis.get("foo");        //取出的值为bar,所以相等        assertEquals("bar", value);        //由于不存在名为bar的key,所以取出来的值为null        assertEquals(null, jedis.get("bar"));    }    @Test    public void getSet() {    //将foo的值设为bar，并返回foo的旧值        String value = jedis.getSet("foo", "bar");        //旧值为null        assertEquals(null, value);        value = jedis.get("foo");        assertEquals("bar", value);    }    @Test    public void mget() {    //mget:返回所有(一个或多个)给定key的值        List<String> values = jedis.mget("foo", "bar");        List<String> expected = new ArrayList<String>();        expected.add(null);        expected.add(null);        assertEquals(expected, values);        jedis.set("foo", "bar");        expected = new ArrayList<String>();        expected.add("bar");        expected.add(null);        values = jedis.mget("foo", "bar");        assertEquals(expected, values);        jedis.set("bar", "foo");        expected = new ArrayList<String>();        expected.add("bar");        expected.add("foo");        values = jedis.mget("foo", "bar");        assertEquals(expected, values);    }    @Test    public void setnx() {    //setnx：将key的值设为value，当且仅当key不存在        long status = jedis.setnx("foo", "bar");        assertEquals(1, status);        assertEquals("bar", jedis.get("foo"));        status = jedis.setnx("foo", "bar2");        assertEquals(0, status);        assertEquals("bar", jedis.get("foo"));    }    @Test    public void setex() {    //给foo设置生存时间设为20秒,值为bar        String status = jedis.setex("foo", 20, "bar");        assertEquals("OK", status);        //返回foo的剩余生存时间        long ttl = jedis.ttl("foo");        assertTrue(ttl > 0 && ttl <= 20);    }    @Test    public void mset() {    //mset:同时设置一个或多个key-value对        String status = jedis.mset("foo", "bar", "bar", "foo");        assertEquals("OK", status);        assertEquals("bar", jedis.get("foo"));        assertEquals("foo", jedis.get("bar"));    }    @Test    public void msetnx() {    //msetnx:同时设置一个或多个key-value对，当且仅当key不存在        long status = jedis.msetnx("foo", "bar", "bar", "foo");        assertEquals(1, status);        assertEquals("bar", jedis.get("foo"));        assertEquals("foo", jedis.get("bar"));        status = jedis.msetnx("foo", "bar1", "bar2", "foo2");        assertEquals(0, status);        assertEquals("bar", jedis.get("foo"));        assertEquals("foo", jedis.get("bar"));    }    @Test(expected = JedisDataException.class)    public void incrWrongValue() {        jedis.set("foo", "bar");        //foo的值是字符串类型，执行incr函数即抛出异常        jedis.incr("foo");    }    @Test    public void incr() {    //如果foo不存在，以0为foo的初始值，然后执行INCR操作        long value = jedis.incr("foo");        assertEquals(1, value);        value = jedis.incr("foo");        assertEquals(2, value);    }    @Test(expected = JedisDataException.class)    public void incrByWrongValue() {        jedis.set("foo", "bar");        //foo的值是字符串，给他增加2净抛出异常        jedis.incrBy("foo", 2);    }    @Test    public void incrBy() {    //如果foo不存在，以0为foo的初始值，然后执行INCRBY命令，增加2。        long value = jedis.incrBy("foo", 2);        assertEquals(2, value);        value = jedis.incrBy("foo", 2);        assertEquals(4, value);    }    @Test(expected = JedisDataException.class)    public void decrWrongValue() {        jedis.set("foo", "bar");        //foo的值为字符串，不能操作减一        jedis.decr("foo");    }    @Test    public void decr() {    //如果foo不存在，以0为foo的初始值，然后执行DECR操作。        long value = jedis.decr("foo");        assertEquals(-1, value);        value = jedis.decr("foo");        assertEquals(-2, value);    }    @Test(expected = JedisDataException.class)    public void decrByWrongValue() {        jedis.set("foo", "bar");        //foo的值为字符串，不能操作减2        jedis.decrBy("foo", 2);    }    @Test    public void decrBy() {        long value = jedis.decrBy("foo", 2);        assertEquals(-2, value);        value = jedis.decrBy("foo", 2);        assertEquals(-4, value);    }    @Test    public void append() {    //foo不存在，给foor的值设为bar，返回append后的值长度        long value = jedis.append("foo", "bar");        assertEquals(3, value);        assertEquals("bar", jedis.get("foo"));        //再次append,在之前的值之后        value = jedis.append("foo", "bar");        assertEquals(6, value);        assertEquals("barbar", jedis.get("foo"));    }    @Test    public void substr() {        jedis.set("s", "This is a string");        //截字符串操作，没什么好说的        assertEquals("This", jedis.substr("s", 0, 3));        assertEquals("ing", jedis.substr("s", -3, -1));        assertEquals("This is a string", jedis.substr("s", 0, -1));        assertEquals(" string", jedis.substr("s", 9, 100000));    }    @Test    public void strlen() {        jedis.set("s", "This is a string");        assertEquals("This is a string".length(), jedis.strlen("s").intValue());    }    @Test    public void incrLargeNumbers() {        long value = jedis.incr("foo");        assertEquals(1, value);        assertEquals(1L + Integer.MAX_VALUE, (long) jedis.incrBy("foo",                Integer.MAX_VALUE));    }    @Test(expected = JedisDataException.class)    public void incrReallyLargeNumbers() {        jedis.set("foo", Long.toString(Long.MAX_VALUE));        long value = jedis.incr("foo");        assertEquals(Long.MIN_VALUE, value);    }}